It took me weeks to convince a region of my realm not to hate us and doing the same thing as you (trying to get them to like an ally) isn't going that well for me either. Also you are much more effective when you are trying to improve the view of your own realm instead of someone else's (from in game text: Naturally, your word about your own realm will be believed more than your word about other realms) so I think it's working as intended.
