Well, I thought "dread" was self explanatory anyway lol. AntiochiusIII said it good.

Proposing Cease-Fire:
1. You must not have your troops besieging enemy castle.

2. Pull back your troops from enemy provinces or from the bordering provinces to be sure because they might ask you to do that before they can accept the proposal.

3.You must not have your fleet attacking enemy fleets.

4. Keep proposing if they turn the offer down; they might need couple years to consider your good intentions.

5. Know when to be nice. I mean don't just run away if they invade just because you want to cease fire. Die for your people and kingdom! (sorry, I'm just into it)

I hope that helps a little bit. Powerful kingdoms get cocky though. They refuse proposals a lot. The AI isn't so dumb after all.