竭力完成承诺英语怎么说

"竭力完成承诺" 的英文表达是 "strive to fulfill a promise"。

"Strive" 是一个动词，意思是努力，尽力。"Fulfill" 是一个动词，意思是完成，履行。"Promise" 是一个名词，意思是承诺，保证。

下面是一些英文例句和中文翻译：

I will strive to fulfill my promise to help you with your homework every day. (我会竭力帮助你每天完成家庭作业。)
He always strives to fulfill his promises to his customers. (他总是竭尽全力履行他对客户的承诺。)
She made a promise to herself to lose weight, and she is striving to fulfill it. (她向自己承诺减肥，她正努力履行这一承诺。)