Backstory
During a session recently played, an NPC asked my character a question. I answered the question. The DM, after hearing a die roll, told me to roll a bluff check. I told him I wasn't lying.
He said, "You still need to make a check to see if he believes you or not."
I told him, "I am telling the truth, it is his choice to believe me or not, not a die roll."
Then he said, "You will get a bonus for telling the truth."
Of course, I didn't have Bluff as a class skill, and had no ranks in it, and rolled rather lousily.
He then told me, "The NPC is having a hard time believing that." I indiscreetly shook my head and gave a nod of acknowledgement.
Favorable and unfavorable circumstances weigh heavily on the outcome of a bluff. Two circumstances can weigh against you: The bluff is hard to believe, or the action that the target is asked to take goes against its self-interest, nature, personality, orders, or the like. If it’s important, you can distinguish between a bluff that fails because the target doesn’t believe it and one that fails because it just asks too much of the target. For instance, if the target gets a +10 bonus on its Sense Motive check because the bluff demands something risky, and the Sense Motive check succeeds by 10 or less, then the target didn’t so much see through the bluff as prove reluctant to go along with it. A target that succeeds by 11 or more has seen through the bluff.
I do not see anything above that mentions a bonus for telling the truth, or even needing to roll when telling the truth.
Question(s)
- Is there any information from another book on expanded uses of the
bluff skill that I am unaware of? - Or is this strictly a case of the DM using his authority?
- If if isn't necessary, are there circumstances when it should be
necessary?
Best Answer
By the rules, I can't recall anything that says out loud that you are supposed to roll a bluff check in that event, so (unless disproven, because proving negatives is impossible unless I read all the D&D 3.x material again) I'd say this is a case of the DM using his authority to ask for a roll.
Now, was what he asked fair?
Of course this is deep into the speculation zone, but I think it has a solid basis.
Since the rules tell nothing about rolling to disbelieve true things, your DM could have just said, "No, the NPC does not believe that you're telling the truth. In fact, he believes you're either lying in a very convincing way or you've been fooled into believing by someone else."
Diplomacy, bluff or charisma checks of any sort are useless to convince him you've not been fooled, unless you're known for not being gullible (and in that case, they're an automatic success).
Bluff is not really great even for convincing someone you're not lying: I would have asked for a diplomacy check instead. Truth is, bluff is often used to represent body language (I think it was used to relay messages to people not speaking your language, but that might just be my DM's ruling), so I see your DM's reasoning.
Were you better at diplomacy than bluff, I'd see a problem in your game. If not, he just gave you a (small) chance to luckily shine.