is this sentence correct or wrong?

[Qurban Ali]

he keeps his promise.(means he fulfill his promise)

[englishhobby]

It's correct. E.g. -> He always keeps his promise. = He always does what he says he will do.

[5jj]

I have moved this thread to a more appropriate forum.

Qurban Ali. Please try to give your threads more helpful titles. "He always keeps his promise. Correct?" would have been fine for this.

[Amigos4]

he keeps his promise.(means he fulfill his promise)

Qurban Ali, please allow me to correct your original post. All sentences in English must begin with a capital letter! Therefore, your sentence must be: 'He keeps his promise.'

Welcome to the forums!

[emsr2d2]

Welcome to the forum.

You have already been told to start every sentence with a capital letter so there's no need to repeat that. I find your sentence a little unnatural. I would expect to hear either "He keeps his promises" when talking about a habitual action or "He kept/will keep his promise" when talking about one specific promise. The present tense doesn't really work with the singular.

If you are going to use "correct", then use "incorrect" as the opposite. If you want to use "wrong", then use "right". It's unnatural to put "correct" and "wrong" together, or to put "right" and incorrect" together.