The knight in "The Wife of Bath's Tale" doesn't make a very good first impression, and he's not a very good knight. Knights are supposed to protect women; instead, he rapes one. Knights are supposed to keep their promises steadfastly; he whines and complains and tries to wriggle out of his when it turns out that keeping his promise requires him to marry the loathly lady. Knights are supposed to be respectful of their elders; on his wedding night, he tells the loathly lady to her face that she's ugly, old, and low-born.
The knight may not be very likable, and he may not be a very good knight, but he's teachable. By the end of the tale, he gives up his power to his wife completely and graciously says, "I put me in your wise governance" (1237). After this statement, we want to believe he's reformed, and can almost forgive him for what a jerk he's been in the course of the tale. The knight is probably meant as a symbol of all men in a tale whose point seems to be that men need to be taught to listen to women's desires and yield sovereignty to them. The knight eventually learns his lesson, although it takes him a while. With him, then, the tale seems to be encouraging women not to give up hope on the men in their lives; they may make some mistakes, but they'll come around in the end.