YOU SAID:

I can not believe you would drive your car off a cliff

INTO JAPANESE

車を崖から突き落とすなんて信じられない

BACK INTO ENGLISH

I can't believe you pushed your car off a cliff

INTO JAPANESE

あなたが車を崖から突き落としたなんて信じられない

BACK INTO ENGLISH

I can't believe you pushed your car off a cliff