From Chapter 57
' “Lizzy,” said her father, “I have given him my consent. He is the kind of man, indeed, to whom I should never dare refuse anything, which he condescended to ask. I now give it to you, if you are resolved on having him. But let me advise you to think better of it. I know your disposition, Lizzy. I know that you could be neither happy nor respectable, unless you truly esteemed your husband; unless you looked up to him as a superior. Your lively talents would place you in the greatest danger in an unequal marriage. You could scarcely escape discredit and misery. My child, let me not have the grief of seeing you unable to respect your partner in life. You know not what you are about.”
Elizabeth, still more affected, was earnest and solemn in her reply; and at length, by repeated assurances that Mr. Darcy was really the object of her choice, by explaining the gradual change which her estimation of him had undergone, relating her absolute certainty that his affection was not the work of a day, but had stood the test of many months' suspense, and enumerating with energy all his good qualities, she did conquer her father's incredulity, and reconcile him to the match.'
It's a romantic novel and we don't follow them into married life. But I think we are meant to understand that Elizabeth has had a chance to think again about Darcy after her first refusal of him - and has a better estimation of his true character.