Where is the fun in that, monsieur? There is a certain charm to watching a person's eyes go wide in realization as they're being "betrayed". Concealment and disguises are a specialty of mine, you see—I hardly kill with the same face. A wife turning on a husband, a friend turning on a friend, it's all too believable with the right circumstances, non?

...unless of course, it is as simple as a knife to the back. Trite perhaps, but it gets the job done. 

[ Sure let's just talk about how we murder people, this is normal conversation. Better than flirting(?) but probably only just, because it's not like he's a stranger to that either. Usually it's the other way around though, and he does prefer ladies.]