I once had someone ask me when I thought Darcy fell in love with Elizabeth and I answered when she came to Netherfield to care for Jane, and when rereading it, this is even more affirmed for me. I love the little line after Mrs. Bennet and the other Bennet girls leave Netherfield and Lizzie goes back up to Jane- Miss Bingley and Mrs. Hurst start roasting Elizabeth but then “(Mr. Darcy) could not be prevailed on to join in their censure of her, in spite of all Miss Bingley’s witticisms on fine eyes.”
Aka: two ladies of “class” start dragging Lizzie, and practically goading Darcy into saying something by teasing about his fine eyes remark, but Darcy keeps his mouth shut because something is stirring inside him. He sees how Lizzie treats her sister, he understands how embarrassed she is of her family’s poor manners. He realizes her intelligence and lively mind, and dang he is falling in love FAST but doesn’t know how to handle himself

Lizzie and Darcy have their first lovely conversation over the weight of friend’s advice in decision making and thus begins Darcy’s ardent passion for Miss Elizabeth, also known as the beginning of him staring her down whenever they’re together just in complete agony