"Tu me plais"
Translation: I have a crush on you/ I like you
In other words: "plaire" is "to please" and not "to be pleased". The subject and object are switched compared to the English phrases (e.g. "I like you").
There are a few other such French verbs that switch subject and object when translated into English because there is no such verb (or phrase) in English. For example: "Tu me manques" is "I miss you", because manquer means "to be missing" and not "to miss".
"Tu me plais" is literally "You please me", but the meaning is closer to "I like you (you are pleasant to me)". This meaning has been culturally intensified to "I have a crush on you."
