YOU SAID:

I didn't know you were going to new York City

INTO JAPANESE

私はあなたがニューヨークに行くことを知らなかった

BACK INTO ENGLISH

I did not know that you would go to New York

INTO JAPANESE

私はあなたがニューヨークに行くことを知りませんでした

BACK INTO ENGLISH

I did not know that you would go to New York