Fails

Bill often fails to keep his word.

Bill never fails to send a birthday present to his mother.

Nancy never fails to write to me once a month.

Nancy never fails to arrive on time.

Tom often fails to keep his word.

Tom never fails to send a birthday present to his father.

If he fails, so what?

Everybody fails once or twice.

My daughter never fails to write to me at least once a week.

Whether he succeeds or fails, he has to do his best.