YOU SAID:

I can't believe I've misplaced my huge hat again.

INTO JAPANESE

私は私の巨大な帽子をもう一度置き忘れたとは信じられません。

BACK INTO ENGLISH

I can not believe that I left my huge hat again.

INTO JAPANESE

私は再び私の巨大な帽子を残したとは思えません。

BACK INTO ENGLISH

I do not think I left my huge hat again.

INTO JAPANESE

私は再び私の巨大な帽子を残したとは思わない。

BACK INTO ENGLISH

I do not think I left my huge hat again.