YOU SAID:

How does anyone know that I am mortal if I have not died yet?

INTO JAPANESE

私がまだ死んでいなければ、だれが私が死に至っていることをどのようにして知るのでしょうか。

BACK INTO ENGLISH

If I was not dead yet, how would I know that I had died?

INTO JAPANESE

私がまだ死んでいなければ、自分が死んだことをどうやって知ることができるでしょうか。

BACK INTO ENGLISH

If I was not dead yet, how can I know that I was dead?

INTO JAPANESE

私がまだ死んでいないのであれば、どうすれば自分が死んだことを知ることができますか？

BACK INTO ENGLISH

If I was not dead yet, how can I know that I was dead?