says,

“Elinor … possessed a strength of understanding, and coolness of judgment, which qualified her, though only nineteen, to be the counsellor of her mother.”

Elinor's "feelings were strong; but she knew how to govern them.” This is key to understanding the difference between the two sisters. Elinor feels things deeply but she knows how to control and often mask her feelings. Conversely, Marianne is in love with romance and the idea of masking or controlling her feelings is anathema to her.

When Colonel Brandon says of Marianne, “there is something so amiable in the prejudices of a young mind, that one is sorry to see them give way to the reception of more general opinions," Elinor disagrees. She believes that Marianne's intense emotions and the way she embraces romance are too extreme. Marianne is the sensibility to Elinor’s sense. The author specifically says, “Elinor saw, with concern, the excess of her sister's sensibility.”

Austen says that

Marianne's abilities were, in many respects, quite equal to Elinor's. She was sensible and clever,

but unlike Elinor, who can control her feelings, Marianne’s “sorrows, her joys, could have no moderation.”

Austen describes Marianne as

everything but prudent. The resemblance between her and her mother was strikingly great.

The reader can surmise that the contrast between Marianne and Elinor, with respect to their emotions, is also “strikingly great.”

The way the two sisters feel the pain of lost love is similar to the way they feel the pain of their father's death. Marianne becomes sick with emotions following Willoughby's betrayal, while Elinor puts on a brave face after she learns that Edward is engaged.

Elinor Dashwood and her sister Marianne begin as complementary opposites, but during the course of the novel their personalities grow more similar. Their father's death is a burden on them, but grief is not emphasized. The upheaval of moving and reduced circumstances is severe, however.

Elinor has good common sense and, being the oldest of the three sisters, has the most responsibility in the family to help their mother and manage the household. While she suffers terribly from the loss of their father, she acknowledges the challenges that the family is facing.

Marianne is very different. She is uninhibited, and cherishes her irresponsibility. She defends her point of view loudly and tactlessly criticizes her sister. This lack of inhibition threatens to endanger her reputation when she takes up with Willoughby, such as driving around the countryside.

When Elinor finds out that Lucy is engaged to Edward, she basically does nothing. She keeps the confidence entrusted in her, bottles up her emotions, and tries to behave as if nothing had changed. She maintains this posture even when she thinks that they are married. But in the end, when she finds out that it is not Edward but his brother Robert that Lucy has married, she completely falls apart, weeping for joy.

Marianne becomes obsessed with Willoughby. When she realizes that he has thrown her over, she is overcome with melancholy. Disregarding her health, she goes walking in bad weather. This results in her catching a cold, which turns into a severe illness (possibly pneumonia) that almost kills her. Colonel Brandon plays an essential role in aiding her recovery. In the end, she becomes as devoted to him in her way as he has been to her.

Near the start of Sense and Sensibility, we learn that Mrs. Dashwood has been recently widowed. Unfortunately, she and her late husband had no son together, and her husband's first marriage produced a son; therefore, Mr. Dashwood's estate passes to that son rather than to his wife and daughters—Elinor and Marianne. As a result of this law of primogeniture, the women must relocate from a rather large estate to a small cottage. Of course, all of the women mourn the loss of the patriarch as their husband and father, respectively, but the financial and domestic circumstances form the basis of much of Austen's plot.

Generally speaking, Mrs. Dashwood and her daughters are close and are interdependent. They enjoy each other's company, despite their differences. As the title suggests, one of the sisters is ruled by "sense" or logic and reason, and the other by her "sensibility," or emotions. Part of what the sisters must do in the wake of their father's death is try to find a suitable match so they can improve their status. The sisters naturally approach this quest differently because of their distinct personalities. The elder sister Elinor is more prudent and even seems to be without emotion at times, while the younger Marianne is sensitive and volatile. She quickly falls in love with Willoughby, but their relationship falls through and she ends up marrying the dependable but less exciting Colonel Brandon. Meanwhile, Elinor opens herself up to love and finds a match in Edward Ferrars. Both women make good marriages and will prosper after their father's death, though they do regret having to leave their dear mother.

Jane Austen describes the Dashwood sisters as handling life after their father's death by basically carrying on with their own lives. Elinor becomes engrossed in getting to know Edward. She continues her drawing and engages with Edward in conversations about his tastes in books and art (. Ch. 4). Elinor also copes with life by deciding that they should move away from Norland, so that they are not embarrassed in front of their friends by their new impoverished state; thus, she encourages her mother to accept the Barton Cottage in Devonshire.

One way that Marianne is described as coping with life after her father's death is by comforting their mother with affection (Ch. 4).  Also, both daughters and the mother deal with life by crying as they prepare to leave Norland, Marianne proclaiming, "Dear, dear Norland!...when shall I cease to regret you!" (Ch. 5). Finally, they deal with life after their father's death by being determined to adjust to life in their new "poor and small" cottage and by being "resolved to appear happy" and be cheerful (Ch. 6).

The usual take on Elinor and Marianne is that Elinor is the reserved, rational one, and Marianne is the emotional, Romantic one. There is plenty of evidence in the book to support this interpretation, beginning with the initial description of the sisters in the first chapter: Elinor “possessed a strength of understanding, and coolness of judgment, which qualified her, though only nineteen, to be the counsellor of her mother,” while Marianne “was sensible and clever; but eager in everything: her sorrows, her joys, could have no moderation. She was generous, amiable, interesting: she was everything but prudent.”

But maybe the best way to understand this pair is to consider what they share, which is the problem of being a woman without property in Regency England, or, more specifically, the problem of being attached to men (Edward and Willoughby) who are false: Edward conceals his engagement to Lucy, and Willoughby, himself in want of money, drops the penniless Marianne to chase the heiress Sophia Grey. Their reactions are consistent with their personalities: when Lucy tells Elinor about her engagement, Elinor, though reeling, agrees to keep her secret. Marianne also is devastated by Willoughby’s cold behavior to her when they finally meet in London; in this case, her “understanding” with Willoughby is a secret that she is unable to keep (she falls into depression and mopes for days). Each sister, however, is bound by hopes that they dare not openly speak about; even Marianne, for all her lack of “prudence,” affirms to Elinor that she was never actually engaged to Willoughby, although “'I felt myself…to be as solemnly engaged to him, as if the strictest legal covenant had bound us to each other.’” In this sense one can understand the “sense/sensibility” dichotomy as different reactions to the same fundamental problem, which is the silence imposed on women. Neither Marianne or Elinor can give voice in any direct way to their desire, and it is their relationship to desire that shapes their personalities (cool or passionate, calculating or impulsive). It is a misreading, in my opinion, to see Elinor as the “smart” one or the one who comes out best; the point of the book instead is to show how each woman grows while trying to navigate the social relations that bind them.

Elinor and Marianne Dashwood have very disparate personalities. Elinor is reserved and tends to bottle up her feelings, while Marianne is overly dramatic. Elinor feels it her duty to make sure everyone else's needs are met while Marianne often does not even notice others needs. These two characters both have a strong reaction to their father's death. While Marianne expresses her grief through music and other such outlets, Elinor finds quiet moments alone to shead her tears. Both characters find it difficult to adjust to their new life without their father. They have both lost their fortune and their dowries. Both must find a husband or some other way to survive on their limited income.