YOU SAID:

i'm going to a party tonight

INTO JAPANESE

私は今夜パーティーに行くよ

BACK INTO ENGLISH

I go to the party tonight.

INTO JAPANESE

私は今夜パーティーに行きます。

BACK INTO ENGLISH

I will go to the party tonight.

INTO JAPANESE

今夜のパーティーには行きますか。

BACK INTO ENGLISH

Will you go to the party tonight?

INTO JAPANESE

今夜のパーティーには行きますか。

BACK INTO ENGLISH

Will you go to the party tonight?