YOU SAID:

I thought I was the only one for you.

INTO JAPANESE

私はあなただけが私だと思った。

BACK INTO ENGLISH

I thought that you alone.

INTO JAPANESE

私はあなた一人だと思いました。

BACK INTO ENGLISH

I thought you were alone.

INTO JAPANESE

私はあなたが一人だと思った。

BACK INTO ENGLISH

I thought you were alone.