One problem that I have with the various ways of determining falsehood in 3.5/PF is that none of them are foolproof. There are a few spells that help with this, but they all allow saves. Zone of Truth is especially bad, since you don't even know if a particular character failed the save or not, and the affected character is aware of the effect and can clam up if they want.
Is there a way to force a character to tell the truth (or at least know if they're lying) that doesn't allow a save, or SR, or any other form of resistance? I'd be happy with answers that just get by save and SR, as I feel that it's unlikely that anything is going to get by Mind Blank or other such total protections. I'm happy with answers that address either 3.5 or Pathfinder, but please note which you're answering.