誰に対しても

toward anyone

→ 誰
phrase Rare #33,550
toward anyone Means toward everyone or anyone, regardless of who they are. に対して indicates the person an action, attitude, or feeling is directed toward, and も adds the sense of “any” or “every.”
JA: 彼は誰に対しても親切です。
EN: He is kind to everyone.

彼女は誰に対しても感じがいい

She is friendly to everyone.

彼は異議唱える誰に対しても腹を立てた

He got angry with anyone who disagreed with him.

彼女は誰に対してもとても親切だった

She was very kind to everyone.

ネルソン・マンデラ誰に対しても礼儀正しく丁寧でした

Nelson Mandela was polite and courteous to everyone.

彼女は誰に対しても親切だった

She was kind to everyone.