YOU SAID:
I need to go to the bathroom, I'll be back
INTO JAPANESE
私はバスルームに行く必要があります、私は戻ってきます
BACK INTO ENGLISH
I need to go to the bathroom, I will be back
INTO JAPANESE
私はバスルームに行く必要があります、私は戻ってくる
BACK INTO ENGLISH
I need to go to the bathroom, I will come back
INTO JAPANESE
私はバスルームに行く必要がある、私は戻ってくる
BACK INTO ENGLISH
I need to go to the bathroom, I will come back
You've done this before, haven't you.