YOU SAID:

I know you're seeing her

INTO JAPANESE

私は彼女を見ている知っています。

BACK INTO ENGLISH

I have seen her know.

INTO JAPANESE

私は彼女を知っているを見ています。

BACK INTO ENGLISH

I know she looked.

INTO JAPANESE

私は彼女を見た知っています。

BACK INTO ENGLISH

I saw her you know.

INTO JAPANESE

あなたが知っている彼女を見た。

BACK INTO ENGLISH

You saw her you know.