"It's not easy," Terrence said, covering his hand with hers. "You have to find a way, in your mind, to see your target as something less than human. If you can't see them as anything other than as human as they appear to be, it won't work. I've seen it happen, people get cold feet."
He looked at her very seriously. "Usually, you won't be required to just outright kill someone. You lead up to it first, and if you can get into the mindset for torture - which is pretty easy by the time they ask you to kill - then you'll probably be alright."
With a small smile, he ran his thumb over her knuckles. "You've got a few years to learn and practice before you get there, though."