YOU SAID:
I don't understand how you could 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
Well done, yes, well done!