YOU SAID:
Why you sad i dont know i dont know
INTO JAPANESE
なぜあなたは僕が知らないのか知りません
BACK INTO ENGLISH
I do not know why you do not know
INTO JAPANESE
なぜあなたが知らないのかわからない
BACK INTO ENGLISH
I do not know why you do not know
You've done this before, haven't you.