YOU SAID:

This isn't the thing I think it is.

INTO JAPANESE

これは私が思うところではありません。

BACK INTO ENGLISH

This is not what I think.

INTO JAPANESE

これは私の考えではありません。

BACK INTO ENGLISH

This is not my opinion.

INTO JAPANESE

これは私の意見ではありません。

BACK INTO ENGLISH

This is not my opinion.