]At this accidental meeting at Pemberley, both Lizzy and Darcy are surprized, and embarassed. Lizzy certainly expected Darcy to avoid her, and probably Darcy must have felt the same about her.

You are right. In the book we know that:-

" ...in spite of all his endeavours, he had found impossible to conquer; and with expressing his hope that it would now be rewarded by her acceptance of his hand."

And in P&P2 just before the 'accidental meeting', we see Darcy trying to conquer his emotions and deep love to Lizzy. But it appears in both cases that he doesn't have any control of that love anymore.

]I think, it took a lot of determination, and humility for Darcy to have gone looking for her again, and to extend his civilities to the Gardiners.

Oh, yes ,poor Darcy it seems here that love conquers him eventually, and we are lucky that dear Lizzy at last began to look at him differenly and with an eye of sympathy.

]Let's see what happens next...:)