His father smiled weakly in a forlorn attempt to reassure him that everything was all right.

他父亲淡淡地一笑，枉然地试图要他放心，一切都安然无恙。

《牛津词典》

I hastened to reassure him.

我赶忙使他放心。

youdao

You may also want to reassure him that you value your relationship.

你可能还要让其放心，你是珍惜双方之间的关系的。

youdao

Her words and gesture were intended to reassure him and let him know that she understood his frustration and appreciated his efforts.

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Bush said he phoned Putin recently to reassure him on both issues.

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France's president, Nicolas Sarkozy, summoned Corporal Shalit's father to Paris to reassure him that his son, a dual French-Israeli citizen, was still alive.

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