Romeo is an Italian youth for whom l'amore (=love in Italian) is everything.
At first Romeo is somewhat comical when he tries to play the role of the Petrarchan lover as he is very dramatic in his speech, and his love is unrequited. For instance, he uses oxymorons such as "heavy lightness" and "loving hate." He composes his verse to a woman named Rosaline, whom he does not know well, and he seems to be more preoccupied with the sensations and expressions of love than he is in expressing true emotional feelings. He later learns that Rosaline is indifferent towards him, and his love is not returned.
After he meets Juliet, Romeo's conception of love changes as he experiences tremendous emotional and physical attraction to her. It is then that he realizes his love for Rosaline was not real love:
Did my heart love till now? Forswear it, sight!
For I ne'er saw true beauty till this night. (1.5.53-54)
While Romeo has matured in his conception of love, he yet remains immature and impulsive in the expression of his love. For example, he climbs the orchard wall in order to stand beneath Juliet's balcony even though he could be killed by Capulet guards if discovered in this act. Then, when he impulsively injects himself into the argument of Mercutio and Tybalt, rather than defusing the situation, he flames the fires of hatred in Mercutio. He angers Mercutio as he seems to submit to Tybalt by expressing love for this enemy of the Montagues without explaining why he has changed his mind. However, when Tybalt stabs Mercutio, Romeo impulsively slays Tybalt, reverting to his stronger love for Mercutio. By killing Tybalt, Romeo selfishly and immaturely ignores the fact that Tybalt is the beloved cousin of his wife and that the Prince has forbidden anyone to fight in the streets of Verona.
Once he learns that he is banished from Verona, Romeo goes to the cell of Friar Lawrence. He worries that Juliet no longer loves him, and he wants to end his life. The friar explains that once matters quiet down Prince Escalus may change his mind about Romeo's banishment. When the Nurse brings the ring from Juliet and arrangements are made for Romeo to visit Juliet before he must depart, Romeo's heart is lifted as his love for Juliet is sustained.
After he spends the night with Juliet, Romeo must depart before it becomes light. However, overcome by his love, Romeo insists that he will remain with Juliet because he does not care if he is killed by the Prince’s men. Juliet insists that he leave, so he does out of respect for Juliet's love. While he is in Mantua, a plague prevents the messenger from giving Romeo the notification from Friar Lawrence about Juliet's false death. Hearing later that Juliet is dead, Romeo screams, "Then I defy you stars" (5.1.24). Romeo still affirms his love for Juliet, the love that is all for which he has lived. Finally, when Romeo finds Juliet dead in the tomb, he kills himself because of his all-consuming love for her. To Romeo, life is nothing without his beloved Juliet.