YOU SAID:

If I can prove them wrong I will be very happy and sad at the same time.

INTO JAPANESE

それらが間違っていることを証明できれば、私は非常に幸せであると同時に悲しいでしょう。

BACK INTO ENGLISH

If I could prove that they were wrong, I would be very happy and sad at the same time.

INTO JAPANESE

それらが間違っていたことを証明できれば、私はとても幸せであると同時に悲しいでしょう。

BACK INTO ENGLISH

I would be very happy and sad if I could prove that they were wrong.

INTO JAPANESE

彼らが間違っていたことを証明できれば、私はとても幸せで悲しいでしょう。

BACK INTO ENGLISH

I would be very happy and sad if I could prove that they were wrong.