YOU SAID:
A ministering angel shall my sister be
INTO JAPANESE
救いは、私の妹をしなければならないこと
BACK INTO ENGLISH
Salvation is not having my sister
INTO JAPANESE
救いは、私の妹を持っていません。
BACK INTO ENGLISH
My sister has no salvation.
INTO JAPANESE
私の妹には救いがありません。
That didn't even make that much sense in English.