Quote Originally Posted by Macilrille View Post
A better plan is to invade all provinces in the border region, sack them, leave them and let them rebel (or give them to another faction). When you no longer has a land border with them, they will stop attacking you and likely sue for peace.
Letting them rebel is probably the better choice - the faction you give them to will probably attack you after a few turns, if they even accept the gift.