YOU SAID:

i have to go to a party

INTO JAPANESE

私はパーティーに行かなければなりません

BACK INTO ENGLISH

I have to go to the party

INTO JAPANESE

君はパーティーに出なくてはならないよ。

BACK INTO ENGLISH

You have to go to the party. [M]

INTO JAPANESE

君はパーティーに出なくてはならないよ。

BACK INTO ENGLISH

You have to go to the party. [M]