YOU SAID:
This person is so stupid
INTO JAPANESE
この人は本当に愚かです
BACK INTO ENGLISH
this guy is really stupid
INTO JAPANESE
この人は本当にバカだ
BACK INTO ENGLISH
this person is really stupid
INTO JAPANESE
この人は本当にバカだ
BACK INTO ENGLISH
this person is really stupid
That didn't even make that much sense in English.