YOU SAID:
I have been in your niece
INTO JAPANESE
あなたの姪に行ったことがあります。
BACK INTO ENGLISH
Have you been to your niece.
INTO JAPANESE
あなたの姪になりました。
BACK INTO ENGLISH
Your niece.
INTO JAPANESE
お前の姪だ
BACK INTO ENGLISH
Your niece.
Come on, you can do better than that.