Fire Truth

You light a specially-made candle and place it within 5 feet of a named target. If the target then knowingly tells a lie, the candle flares brightly. A half-lie or slight deception causes the candle to gutter and flicker. If the target tells an outrageous lie, the candle extinguishes itself. 

At Higher Levels. When you cast this spell using a 5th-level or higher spell slot, and the target tells a lie, the fire leaps and burns the target, inflicting 1d8 fire damage with each lie.