Can i raise the relationship with a country only through paying hard cash or can i do something else? is that maybe that bad boy thingy that i've seen around here somewhere?
Fodoron said:MA, RM, TA. These things do not rely on high relationships, although a high relationship will undoubtely help.
passer by said:MA and TA you probably need +50 or better.
RM is a strange beast, you will ususally get one between -150 and -10, and then again from +40 unpwards.
Best way though is still to get land for allies in peace, and as has been pointed out you only need care what your allies (and potential vassals) think of you and respond to war support.