Try talking to father Rulae. If he attacks you can just kill him for the holy water
If he doesn't attack but doesn't want to talk to you either try until you succeed (cast many charm spells). You can improve both your diplomatic skill and his favor this way.
Or you could try again after killing a few Dane NPCs, Munk and Dane are enemies. But why make the Dane hostile just to please one single remaining Munk ? You've already chosen your side.