What is a willing creature?
Most spells tend to have saving throws, even the cure spells. I know the saving throw is there because they can harm those who have negative energy instead. Generally when a source is a known and trusted person, say the party cleric, no saving throws are made. Yet, I cant find a rule which allows this. Spell resistance for example always applies unless they take an action to lower it.
The reason why I am asking this is because of that trust factor. I am in an evil game, eventually I plan on posing as a good cleric and helping people. After I have done this for awhile I expect to start using harmful spells, possibly even baleful polymorph. As I have worked to build up the reputation, and they have been accepting spells from me, provided there is no reason to suddenly distrust me, would they be affected by the spell(s) with no saves or not?
There is also the possibility that I will be pretending to be known people, using claim identity, so as long as they fail to see past it, would they be willing.
As pointed out in the comments, the question is very similar to this one. So to tell them apart I will ask for clarification in the answer to it, at what point has the subject/target of a spell final in terms of willing or not? Unless they pass a spellcraft to know what spell(s) I am casting, a cleric who has been healing the town for months should be trusted and someone should just be accepting of a spell.