YOU SAID:
They don't get to know what I said!
INTO JAPANESE
彼らは私が言ったことを知ることはできません!
BACK INTO ENGLISH
They can not know what I said!
INTO JAPANESE
彼らは私が言ったことを知ることができません!
BACK INTO ENGLISH
They can not know what I said!
That didn't even make that much sense in English.