The verb mollify means to do or say something to someone to make them less upset or angry.
Synonyms are pacify, soothe, appease, or alleviate.
The word origins from Old French (late 14th century) mollifier or directly from Late Latin mollificare meaning “make soft, mollify” from mollificus meaning “softening”, from Latin mollis meaning “soft”.
I patted his back gently to mollify him.
He tried to mollify Eva by giving her chocolates.
He’s completely outraged. No one can mollify him.