YOU SAID:
I cannot believe you would kill my cousin
INTO JAPANESE
私はあなたが私のいとこを殺すとは信じられません
BACK INTO ENGLISH
I can't believe you kill my cousin
INTO JAPANESE
私はあなたが私のいとこを殺すとは信じられません
BACK INTO ENGLISH
I can't believe you kill my cousin
That didn't even make that much sense in English.