This last stanza reveals that she has transformed into a beautiful and young woman who was deeply in love and willing to make his husband happy, ( this is proved through the description of the actions they take as soon as they see each other)
Explanation:
The Wife of Bath is a story that shows how after going over a test related to one of the most common doubts in love, what would people prefer a beautiful partner o a faithful one, after having answering correctly we can see that the real prize is the loyalty and faithfulness of a partner which can be bigger of any kind of physical beauty.
