Guarantee of a future war? Also, even if you don't declare a goal to kill the other realm, you can be reasonably sure that they wouldn't surrender. Therefore Sorraine would have to, "with great regret and full of sorrow", put an end to Ohnar West. That's how you play the polotical game. You declare something small, figuring that the other side will push it to the end. But that's their fault, not yours.