YOU SAID:

I will cut of your head

INTO JAPANESE

私はあなたの頭をカットします

BACK INTO ENGLISH

i will cut your head

INTO JAPANESE

私はあなたの頭を切ります

BACK INTO ENGLISH

i will cut off your head

INTO JAPANESE

私はあなたの頭を切り落とします

BACK INTO ENGLISH

i will cut off your head