Vode's Gaze of the Solar

You empower the target with a fraction of divine sense. Until the spell ends, the first time the target hears any creature you speak a language they understand, the creature must succeed on a Charisma saving throw. On a failed save, any lie that creature tells is accompanied by a telepathic sensation. This might take the form of a tone, or change in voice which is known only to the target. You know whether each creature succeeds or fails on its saving throw.

An affected creature is not aware of the spell, and should not change their behavior unless they become aware of the effect by other means.

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When cast at fourth level or higher, rather than just knowing when it hears a lie - it also hears the truth. When a creature fails a Charisma saving throw, any lie they tell is accompanied by the simplest version of the truth, communicated telepathically to the target. This might take the form of an illusory copy of the creature turning to the target to speak the truth, which is only heard by the target.