This spell forces the target to speak only the truth. The Threshold is half the target’s willpower. The target can say something he or she believes to be true, even if it is not. The subject may choose not to speak or to withhold information but cannot directly lie.
The UCAS and CAS consider the use of this spell by law enforcement authorities to be a violation of the suspect’s right against self-incrimination. Other nations have been known to use this spell (among others) to get to the truth in legal cases.