Tips on increasing vassalage success?
I’m the Emperor of the HRE and I really want to vassalize the pope. I’m his rightful liege after usurping the kingdom of Romagna from a previous pope a while ago and I’ve maxed out every other aspect I can think of that increases success like diplomacy, true ruler, army size, reputation, etc. I’ve befriended him, made an alliance, learned his language but I’m still -2 away from being able to vassalize him. I can’t increase culture acceptance with him like I did with his Italian predecessor (who I had to kill because he was paranoid which gives -20) as he’s Swedish and I have no Swedish counties I can send my steward to to increase culture acceptance. Nor can I travel to any Swedish counties with a culture embasador like I did with Italy as Sweden has no holy sights. And I don’t have any census belli on any Swedish counties.
I could murder him and hope to get another Italian (or a culture I have territory in so I can use it to increase culture acceptance) but there’s a chance his replacement has a trait like paranoid or stubborn that gives negative vassalization chance. This guy is literally perfect except that he’s Swedish. I can dejure seize all of his territory but I’m really trying to avoid war with the head of my religion.
Anything else I can try?