Why does Zane end up regretting his deal with the shopkeeper in the novel, On a Pale Horse?

The love stone leads Zane and his magic carpet towards his home, the route he was going to take anyway. The proprietor follows. On the carpet in front of him, Zane can see a beautiful, wealthy-looking woman named Angelica. Suddenly, her carpet falters and she starts to fall. However, the proprietor acts first, saving Angelica from certain death. When Zane sees the woman's beauty and wealth, he begins to regret the deal.