Does Ravenbloom Conservatory make you reveal to opponent?

Yes — "reveal" means the card is shown to all players, including your opponent.

Ravenbloom Conservatory's ability uses the game action Reveal, which per Rule 424.1 is "presenting a card to all players" — so the top card of your Main Deck becomes public information during the resolution, then either goes to your hand or gets recycled. The effect is mandatory too: no "may," so you can't decline to reveal (FAQ #8464).