。
She tried to become friends with him.
Literal
She [topic-は] he [with-と] friends [become-に] [tried to-ようとした].
~ようとする means 'try to do,' using the volitional form (~よう) plus とする. It often suggests an attempt — not necessarily a successful one. になる ('become') takes に on the resulting state. The と on 彼 marks the partner in the becoming-friends.