The witch stared at you during your little dilemma, it was pressuring you heavily as you struggled to make a choice.
You then thought, if this time was indeed powerful, she must first test it, but on what? Or who? There were quite a few people on your mind that might be willing to be your test subject, but it was still hard to know if they would actually agree. You looked at the stylish book in your hands, slight dusts of frost sticking to your fingers from the amount of time you have been holding it.
And that was when a thought came through your mind, the seductive shopkeeper/witch was just conveniently standing right in front of you, perhaps you could just cast the spell on her? You are sure that whatever happens, she will probably understand it, hopefully