Smiles would no longer deceive us.
I would call it an Auralizer.
It would be a tiny pin worn by everyone. This device would give off a glow (aura) that mirrored the wearer’s true spirit. From then on, we would only judge people according to their inner beauty. Intentions would speak louder than smiles.
People would no longer fear choosing the wrong words. Political correctness would be obsolete.
First experimental application would be on politicians…
*Nudists are on their own!
(Wonder how they know what the women are thinking?)