YOU SAID:

we have to go to the toilet tomorrow to kill poo

INTO JAPANESE

うんちを殺すために明日トイレに行かなければなりません

BACK INTO ENGLISH

I have to go to the bathroom tomorrow to kill the poop

INTO JAPANESE

私はうんちを殺すために明日トイレに行かなければなりません

BACK INTO ENGLISH

I have to go to the bathroom tomorrow to kill the poop