Area of Dishonesty

You create a magical zone that forces deception in a 15-foot-radius sphere centered on a point of your choice within range. Until the spell ends, a creature that enters the spell's area for the first time on a turn or starts its turn there must make a Charisma saving throw. On a failed save, a creature can only speak in lies while in the radius. You know whether each creature succeeds or fails on its saving throw.

An affected creature is not aware of the spell and can thus cannot avoid answering speaking in lies. Any creature that learns of the spell cannot use deliberate words to get around it, unless those words are already lies. The caster is not affected by the spell.