I think [Grindlewald] was a user and a narcissist, and I think someone like that would use it, would use the infatuation. I don't think that he would reciprocate in that way, although he would be as dazzled by Dumbledore as Dumbledore was by him, because he would see in Dumbledore, "My God, I never knew there was someone as brilliant as me, as talented as me, as powerful as me. Together, we are unstoppable! " Maybe he would take anything from Dumbledore to have him on his side.