"In truth I am not clear on what I could ask from you, at this point, which would be appropriate. Most of the things that are wanted from you are things that Cheliax wants, not that I want, and it is I and not Cheliax who loses here. You could agree that you owed me a future favor appropriate to the real cost to me of my lost pride in this matter; it requires some trust from me to you, that you will repay, but no more trust than you are already being given in some ways."
Say the key words as if they mean nothing, make sure to add some more distracting words later, hope he is that naive and does not know to be wary of Asmodeans bearing bargains...