YOU SAID:
My girlfriend who is not my girlfriend gave me a knife and instructed me to murder my abusive father.
INTO JAPANESE
私のガールフレンドではない私のガールフレンドは私にナイフを与えて、私の虐待的な父を殺害するように私に指示しました。
BACK INTO ENGLISH
My girlfriend, not my girlfriend, gave me a knife and instructed me to kill my abusive father.
INTO JAPANESE
私のガールフレンドではなく、私のガールフレンドが私にナイフをくれ、虐待的な父親を殺すように私に指示しました。
BACK INTO ENGLISH
My girlfriend, not my girlfriend, gave me a knife and instructed me to kill my abusive father.
That didn't even make that much sense in English.