YOU SAID:

I don't understand how you can be so rude

INTO JAPANESE

あなたがどうしてそんなに失礼なのか理解できない

BACK INTO ENGLISH

I do not understand why you are so rude

INTO JAPANESE

なぜあなたはとても失礼なのか分かりません

BACK INTO ENGLISH

I do not know why you are so rude

INTO JAPANESE

なぜあなたがとても失礼なのか分かりません

BACK INTO ENGLISH

I do not know why you are so rude