Thanks for your replies guys, but unfortunately,l the AI are just plain stubborn, and unfortunately my diplomats are losing traits. Its a shame diplomats dont get trait bonuses for giving gifts.
Also, playing a chivalric games seems somewhat financially difficult, being unable to sack cities, having to release prisoners, which in turn gives enemies more resources, and not being able to use spies and assassins. Its hard enough paying upkeep on your armies from a multifront war.
Ive never been fond of giving gifts to my enemies as all that results is continued attacks.
But i guess i would ultimately prefer a challenge in having everyone as an enemy.