[He is silent a long time in reply, thinking that over very carefully.

His tone is very gentle when he finally replies.]

If it's solely concerning what was between you and y-- and Karl, I won't say a word of it.

If it's something that might be used to forward a cure for Tranquility-- Better that you not tell me. [The temptation on Casimir's behalf would be too great. And he's carrying too many secrets around all ready that he's guilty for.]