YOU SAID:
can’t believe it’s been so long
INTO JAPANESE
あまりにも長い間それが信じられない
BACK INTO ENGLISH
It's incredible for so long
INTO JAPANESE
とても長い間信じられない
BACK INTO ENGLISH
I can not believe it for so long
INTO JAPANESE
私はそれほど長い間それを信じることができない
BACK INTO ENGLISH
I can not believe it for so long
That didn't even make that much sense in English.