The Wolf Who Cried Love

"Freezing, Fenrir stared at the girl. His heart quickened, and a strange sensation swirled around his stomach. The girl was beautiful." Fenrir Greyback is a Werewolf: a fearless hunter who enjoys driving fear into his victims. At twenty-five, he certainly had more than enough practice, no one would dare argue against that. So...why can't he kill this one?