man of his word 守信用的人；诚实可靠的人；说到做到的人

【例句】
I stood bail for Roger because, as a man of his word, I'm sure he will turn up to stand trial.
我保释罗杰，我是守信用的人，我保证他将出庭。

If he promises to help you, he sure will. He's a man of his word.
如果他承诺过要帮助你，那么他将会做到。他是一个说到做到的人。