The knight in "The Wife of Bath's Tale" is selfish, desperate, shallow, then wise.
He's selfish and arrogant enough to rape a young maiden in the kingdom simply because she's alone and he's "lusty." The people rise up and demand that justice be done, but the queen intercedes on his behalf by offering him a deal: Within 12 months and a day, he was to learn what women want most. He accepts the deal. Of course, he travels all over the kingdom and asks everyone, never hearing the same answer twice. When he's on his way back home to meet his fate, having failed in his mission, he makes a deal with an ugly old crone: she will tell him the answer if he agrees to marry her. He agrees out of desperation.
When the answer turns out to be the right one--women want to be masters of themselves--the old crone tells him he must marry her, but he begs to be let off the hook because he's shallow. He is forced into it anyway, and when he won't bed his wife, she dresses him down (bookishly), then gives him a choice: You can either have me this way knowing I'll never stray and I'll be the best wife you could want until your dying day OR you can have me young and beautiful and know that other men will want me (and I may want them). He thinks about it, then--apparently having learned from his original challenge--says that the choice is hers. He wisely makes her the master of herself.