"The Wife of Bath's Tale" complements what the Wife reveals about her personal life in the prologue to her tale. She makes it very clear in her prologue that she was most happily married when she had the control of the marriage, not the man. She married several times, some happily, some less so, so she certainly seems to have become her own expert on the subject of marriage.
It is no surprise then when in her tale, the theme of "what women want" comes into play. The essential plot of the tale is that a knight is sent on a quest to find out what women want. The queen sends him on the quest, and if he fails to get the answer, he will die. This entire proposition comes about as a punishment for the knight's rape of a young woman. As the time nears its end, the knight meets an old and unattractive women who says that she knows the answer to the question. She offers the knight the answer in return for his marrying her. He agrees and then she makes one more offer. She is a witch and she can turn herself into a beautiful woman who is unfaithful, or stay an ugly women who will be loyal. The knight wisely tells the lady that she should decide how she wants to live her life--he will accept her decision either way. Because the knight gives this answer, she decides to give him the ultimate reward: a beautiful and faithful wife. The knight knows that the answer to the question "What do women want?" is "to be the one with the power in the relationship." When the knight gives over this power, he saves himself and is given the best of both of worlds.