This is true. Though it's been mentioned in the comics that a lot of his emotions/reactions are fabricated. He feels nothing, so he fakes it which is why he can be smiling and having a good time bashing someones head in, when really it isn't doing anything for him. I'm still undecided as to how much of that I'll be working into my muse, but I believe to some extant it'll be true. She may just be one of the very veryyy few people who learn this about him.
Paranoia doesn't suit him. If he felt that she was ever a real threat, he would have her dealt with. Though he much prefers to have her as an asset.