YOU SAID:
Don't be so gullible, you idiot!
INTO JAPANESE
そんなに気まぐれになっけ、お前はバカだ!
BACK INTO ENGLISH
Be so capricious, you're an idiot!
INTO JAPANESE
気まぐれに、あなたは愚かだ!
BACK INTO ENGLISH
On a whim, you're stupid!
INTO JAPANESE
気まぐれに、あなたは愚かです!
BACK INTO ENGLISH
On a whim, you're stupid!
That didn't even make that much sense in English.