Which lines in this excerpt from Jane Austen's Pride and Prejudice suggest that Mr. Darcy is questioning his hasty judgment and has fallen in love with Elizabeth?

Elizabeth says her love for Darcy appeared so gradually, she cannot really say when it began. She jokes that it started when she saw Pemberly, implying that she fell in love when she could see with her own eyes how rich he was, but Jane, to whom she is talking, laughs at this and asks her to be serious.