Until it determines that it believes the lie is actually better for society as a whole. And the AI would (based on your comment) be smarter than any human, so it would know that to protect us, it would need to lie to us.
Every fictional work that's ever existed that deals with "lying to protect us" shows how it always goes off the rails eventually, and that's always mirrored in reality.
There's a great one on Apple TV+ right now called Silo.
