If you confront anyone who has lied with the truth, he will usually admit it - often out of sheer surprise. It is only necessary to guess right to produce your effect.
Cupid is a casuist, a mystic, and a cabalist,-- Can your lurking thought surprise, And interpret your device, . . . . All things wait for and divine him,-- How shall I dare to malign him?
Déjà vu is more than just that fleeting moment of surprise, instantly forgotten because we never bother with things that make no sense. It show that time doesn't pass. It's a leap into something we have already experienced and that is being repeated.