Here’s a guy who’s a top catch in the country. He could have his pick of women, and ladies like Caroline Bingley are lining up to get his attention. So anyone whom he would pay a little attention to should lap it up like a kitten to cream, right?
Mr. Darcy unexpectedly sees Elizabeth during his annual Easter trip to Rosing Park. She tells him of her favorite walk paths, so that they can have “chance” meetings outdoors without the prying ears of Lady Catherine or Colonel Fitzwilliam. So he picks up her hint, and meets here there day after day to begin courting her. For what other reason would they want some time alone together?
Obviously, a woman so perception and intuitive as Elizabeth Bennet would pick up on his advances? Even Charlotte notices his attention. Surely, Darcy assumed, Lizzy was understanding the purpose of his attention.
So imagine his utter and complete shock at her refusal. That she never desired his good opinion, and that she didn’t even feel gratitude for his attentions. Women. Who can understand them!?