gratitude没有动词形式，中文的感恩是动词，用在英文里可以换其他形式表达。

He folt gratitude to him fer for sanving his life.

他感谢她的救命之恩。

I owe you a great debt of gratitude.

我对你感激不尽。

He smiled at them with gratitude.

他向他们笑了笑表示谢意。

Relief and gratitude were written all over his face

他一脸释然与感激。