She got MoFo to admit his infidelity with a bluff. If it wasn't for the fact that he never loved her it might've been funny to see this villain's reaction at getting NTR'd by... a teddy bear. She'll have him know Mr. Felix Levin is easily twice the man he is, by merely being there when he in comparison has never(!) stayed in the royal bedroom.
Oh and he was going to kill her anyway, someone else just beat him to the punch. He's too dangerous to be left running around free after he's done his job looking for the culprit. Not to mention creepy, now that the real her awakened something disgusting in him.