Be complimentary, but not overly complimentary to where it seems inauthentic.
Do not spoil the impression by being obviously inauthentic.
It seems rather inauthentic for the learner to read scripted dialog on screen.
If your words are positive but your behavior demonstrates fear, then the risk of miscommunication or coming across as inauthentic increases.
When you purchase a ring, always make sure the jeweler has a refund policy just in case the ring turns out to be misrepresented or an inauthentic version.