YOU SAID:
The dullest place in the world might not be my room, it must be the basement.
INTO JAPANESE
世界で最もくすんだ場所は私の部屋ではなく、地下室でなければなりません。
BACK INTO ENGLISH
The darkest place in the world must be the basement, not my room.
INTO JAPANESE
世界で最も暗い場所は、私の部屋ではなく地下室でなければなりません。
BACK INTO ENGLISH
The darkest place in the world must be the basement, not my room.
That didn't even make that much sense in English.