This is the 9469th most frequent Russian word.
узнай
"Find out" or "learn."
Here, 'узнай' is used in the imperative mood, instructing someone to discover or learn something.
Узнай правду обо мне.
Find out the truth about me.
In this sentence, 'узнай' is presented in a hypothetical future context, suggesting an action of discovery that triggers a reaction.
Когда ты узнай эту тайну, ты будешь удивлен.
When you find out this secret, you will be surprised.
Here, 'узнай' is again an imperative used to request the act of learning or discovering information.