。
She is kind to everyone.
Literal
She [topic-は] anyone [to-に][also-も] is-kind.
誰にも + affirmative predicate gives a universal positive: 'to anyone / to everyone.' Question word + も polarizes by predicate — affirmative gets a universal reading ('everyone, anyone, anywhere'); negative gets a universal-negation reading ('nobody, nothing, nowhere'). Worth tracking carefully: the same 誰にも surface can mean 'to everyone' or 'to nobody' depending on whether the predicate is affirmative or negative.