Answer:
First Impressions, the original title of Jane Austen's novel, relates to the topic of prejudice, because the main characters of the story are deceived by their first impressions.
Elizabeth's first impression of Darcy is terrible. During the ball, she hears him saying (about her) "She is tolerable, but not beautiful enough to tempt me". After this, Lizzie's opinion of Darcy was dreadful, and even more when Wickham tells her that Darcy was responsible of his misfortunes. Towards the ending of the book, we can see that Elizabeth and Darcy start developing and leave behind their pride and prejudice, and by the end of the story they end up getting married. On the other hand, Elizabeth has a very good first impression of Wickham, but he ends up taking advantage of her sister and playing with her own feelings.
The title "Pride and Prejudice" is a title that Jane Austen is adviced to give to her book, because her previous book was "Sense and Sensibility" and it was very successful, so using a similar structure on this book could be a good way to advertise it.
Pride and prejudice are the two main traits of the characters of Elizabeth Bennet and Fitzwilliam Darcy. Elizabeth is very prejudiced towards Darcy, especially after that first ball in which he barely dances and she hears him saying what was stated above. When Wickham tells her that Darcy didn't allow him to inherit the properties that Darcy's father promised him, she is quick to believe him (although she has no idea of who this Wickham is). When Elizabeth talks about Wickham with Darcy, the latter says that Wickham is <u><em>"blessed with such happy manners as may ensure his making friends, whether he may be equally capable of retaining them is less certain" </em></u>. As the story develops, we learn that Wickham is a very negative character that took advantage of Georgiana Darcy (Darcy's sixteen year old sister) and then he does the same with Lydia Bennet, but Darcy saves her by giving them some money so that they could get married.
Darcy needs to face his pride in order to finally propose to Elizabeth. He belongs to a different sphere than Lizzie, he is very rich in comparison to her and his family expects him to marry someone of the same class. Moreover, his attitudes were openly questioned by Elizabeth more than once. By the time he takes courage and proposes, Elizabeth says no. At that time, women wouldn't give their opinions so freely, and they wouldn't say no to a man's proposal. Elizabeth says no to Mr. Collins proposal and to the first proposal by Mr. Darcy. Marriage was a (if not "the") safest place for a woman. But Elizabeth standards were different than those of other women, she believed that love was more important than just marrying for stability.
Once Elizabeth learns that Darcy saved her sister and her family's reputation, and he fixes the situation with Jane and Mr. Bingley; Her prejudice and pride fade completly, because she learns the truth about Darcy's character. This change in her attitude is what makes her say "yes" to the second proposal by Mr. Darcy.