...in what I said above, because I do not believe Lizzy was attracted to Darcy prior to the proposal; and given what we know up through Chapter 34, I see no evidence that her level of attraction has changed. But I do believe that the shock of Darcy's proposal has forced Lizzy to take a hard look at herself and her encounters with Darcy.

The tumult of her mind was now painfully great. She ... sat down and cried for half an hour. Her astonishment, as she reflected on what had passed, was increased by every review of it. That she should receive an offer of marriage from Mr. Darcy! that he should have been in love with her for so many months! -- so much in love as to wish to marry her in spite of all the objections which had made him prevent his friend's marrying her sister, and which must appear at least with equal force in his own case -- was almost incredible! .... She continued in very agitating reflections .... (Ch. 34)

I see no evidence here for increased affection, but I see plenty of evidence of Lizzy's review of what had taken place at the proposal and reflection on the many months Darcy's love had been growing. She must have asked herself how he could have believed she was assenting, encouraging him; and this would lead her to think about what she had done and said in former meetings. But now I repeat what I said several days ago (below), so I'll stop.