YOU SAID:
You are my best friend girlfriend!
INTO JAPANESE
あなたは私の親友のガールフレンドです!
BACK INTO ENGLISH
You are my best friend's girlfriend!
INTO JAPANESE
あなたは私の親友のガール フレンドです !
BACK INTO ENGLISH
You're my best friend's girlfriend!
INTO JAPANESE
あなたは私の親友のガール フレンドです !
BACK INTO ENGLISH
You're my best friend's girlfriend!
Come on, you can do better than that.