と親しくなった

became close with

→ と
phrase Rare #27,340
became close with と marks the person someone became close to. 親しくなった is the past form of 親しくなる, “to become close.”
JA: 私は隣に住む人と親しくなった。
EN: I became close with the person who lives next door.

私たちはトムと親しくなった。

We became close with Tom.

私は彼と親しくなった。

I became close to him.

夏休みの間に私は多くの村人と親しくなった。

I got to know many villagers during the summer vacation.

その新入生はケンと親しくなった。

The new student became friends with Ken.

つい最近のアメリカ旅行中に、私はジャックと親しくなった。

I became close friends with Jack during my recent trip to the United States.

学園祭で彼らと親しくなった。

I became close to them at the school festival.