Jane Austen's "Pride and Prejudice" raises important moral issues concerned with the institution of marriage.
The most important one being how much money is necessary for a happy and successful marriage:"Pray, my dear aunt, what is the difference in matrimonial affairs, between the mercenary and the prudent motive? Where does discretion end and avarice begin?" (Ch.27)
Jane Austen does not explicitly answer this question by preaching a moral to her readers;but she puts things in perspective by revealing to us the importance of money in marriage and then leaving it to the readers to decide for themselves what is 'moral' or 'immoral'.
In Ch.33 Col Fitzwilliam Darcy the younger son of an earl and obviously a very rich man hints to Elizabeth that he can't marry her: "Our habits of expense make us too dependent, and there are not many in my rank of life who can afford to marry without some attention to money." Was he being prudent or avaricious in not marrying Elizabeth? Jane Austen leaves it to the readers to decide.
On the contrary, Darcy also a very rich man overlooks Elizabeth's impoverished financial status and goes out of the way to ensure that Wickham marries Lydia so that the Bennet's family honour is intact. His love for her compels him to virtually bribe Wickham his worst enemy into doing so. This clearly establishes that he is a noble and generous person and Elizabeth readily accepts his second marriage proposal in Ch.58.
The change in the minds of the hero and heroine are explained in the following manner:
Elizabeth represents PREJUDICE: Elizabeth is completely cured of her prejudices in Ch 36 when she gradually undergoes a complete change as she reads and rereads Darcy's letter and concludes, "till this moment I never knew myself."
Similarly, Darcy represents PRIDE: In Ch. 58 Darcy reveals to Elizabeth and the readers how he gradually underwent a complete transformation and was completely cured of his pride, "by you I was properly humbled."
The novel is actually over once Elizabeth is cured of her prejudice and Darcy of his pride and these two chapters actually represent the closure of the plot. The rest of the novel forms the 'falling action' of the plot leading to the conclusion with Ch.61 forming the epilogue in which Jane Austen ties up all the loose ends.