YOU SAID:

I know you went out with Brian and he's mine

INTO JAPANESE

私はブライアンと出て、彼は私を知っています。

BACK INTO ENGLISH

I went out with Brian, he knows me.

INTO JAPANESE

私はブライアンと出かけ、彼は私を知っています。

BACK INTO ENGLISH

I went out with Brian, he knows me.