What eluded him was the "why" of the situation. It was obvious that seeing him transformed into a woman was pleasing to her, and that it was a kind of punishment for what she thought he had done to her. What confused him was that his eagerness to get through her punishment as quickly as possible only seemed to increase her delight in the situation. After all, she had put a limitation on her spell (or whatever it was) to make sure that no more than one change took place per day. She had said it was to help prolong the punishment. If that was so, why would Jack's cooperation please her?
Not that he really cared what her motivations were. He only wanted his life back.