Who knows? It appears likely that she wants something from him, if she is, as I'm guessing, the "force" to which the solicit refers; if she is that "force" but doesn't want anything from him, then why is his "soul" the "price" for her answers? What exactly she wants from him is something the story would have to reveal. Maybe she has foreseen that he, by some quirk of destiny, is the one who can help her overthrow his father. Maybe she thrives on breaking the most stubborn of wills, and she thinks that's his. Maybe it's just a case of wanting to turn the tables: the ultimate quest object (the personified "Holy Grail") has been pursued ling enough, ans how she wants to pursue the ultimate questing hero (the "Caped Crusader" who is so doggedly determined that he follows his quests to points where ordinary humans shouldn't be able to go) . Or maybe she just has a thing for bats. If I knew, I wouldn't have said "for some reason." I don't even necessarily mean "obsessed" in any kind of erotic sense, which is why I said she might "want to turn him into her lover or slave."
Here, I think you meant to respond to Sacred Knight, not me; I didn't say anything about Batman loving her and/or letting her get away.also batman let a apokolips psycho get away because he loves her is completely wrong, and OOC for him.