This is a fabulous book, one of my favorites by Jane Austen. First, though, before you can thoroughly answer the question, please make sure you've read the book. It's worth your time, I promise.
Here's a tip: think about the title Pride and Prejudice. Who is prideful in the book and why? Who might be prejudiced against someone, especially someone from another social class?
What, then, comes to mind when you think about the main characters, Lizzie Bennett and Mr. Darcy, and their relationships to pride and to prejudice?
Again, to answer the question, you are going to need to read this wonderful novel. But once you do, I hope that you see how Austen uses these characters to illuminate how pride and prejudice can hinder us in our relationships and in society.
Good luck!