"兑现承诺" (duì xiàn chéng nuò) 可以翻译为 "fulfil a promise" 或 "keep a promise"。
来源: 这个短语来源于英文 "fulfil" 和 "promise"。"Fulfil" 是一个动词，意思是 "实现，履行"。"Promise" 是一个名词，意思是 "承诺，诺言"。
一些英文例句和中文翻译:
I will fulfil my promise to be there for you. (我会兑现我对你的承诺。)
She kept her promise to visit her grandmother every week. (她兑现了她每周拜访奶奶的承诺。)
He made a promise to donate money to the charity and he fulfilled it. (他承诺捐款给慈善机构，并且他履行了这个承诺。)