YOU SAID:

when my best friend died.

INTO JAPANESE

私の親友が亡くなったとき。

BACK INTO ENGLISH

When my best friend passed away.

INTO JAPANESE

親友が亡くなったとき。

BACK INTO ENGLISH

When your best friend dies.

INTO JAPANESE

あなたの親友が死んだとき。

BACK INTO ENGLISH

When your best friend dies.