[x] Get under his skin. Fleshrender doesn't listen to reason. He doesn't think right, seems to spite being told what best serves his interests. The only times he's ever listened to you are when you've made a demand or insulted his pride. He'll back down again. That, or he'll kill you. But that's where things are probably going if you don't act, anyways.
[X] Back up Bell's idea. You can finish making the case. If he thinks Bell is proposing it so you and her can be together, then he can take the idea and never put you together, if he wants. He can think of it as a spiteful jab and decide he's won. It's frightening, it will be a problem, but not as much as letting this continue.