YOU SAID:
I think this website is not not interesting
INTO JAPANESE
このウェブサイトはありません興味深いと思う
BACK INTO ENGLISH
This Web site is not interesting
INTO JAPANESE
この Web サイトは面白くないです。
BACK INTO ENGLISH
This Web site is not interesting.
INTO JAPANESE
この Web サイトは興味深いものではありません。
BACK INTO ENGLISH
This Web site is not interesting.
That didn't even make that much sense in English.