YOU SAID:
I don't know what to wear to this wedding.
INTO JAPANESE
私はこの結婚式に何を着るべきかわかりません。
BACK INTO ENGLISH
I don't know what to wear for this wedding.
INTO JAPANESE
私はこの結婚式のために何を着るかわからない。
BACK INTO ENGLISH
I don't know what to wear for this wedding.
You've done this before, haven't you.