Fenrir was never one for hiding his emotions, mostly because they only ranged from amused to angry on any given day. And Bellatrix had just managed to put a silver lining on his day. If she wasn't a ghost and wouldn't hex him the second he tried it...he could have kissed her. But instead he let out a laugh loud enough to give an echo thru the woods.
"Oh please tell me that this is the truth and you are not just trying to get me to ravage her regardless. Because the truth will just make it that more tasty..."