YOU SAID:
She'll never love me back.
INTO JAPANESE
彼女は二度と私を愛してくれません。
BACK INTO ENGLISH
she will never love me again
INTO JAPANESE
彼女は二度と私を愛さない
BACK INTO ENGLISH
she will never love me
INTO JAPANESE
彼女は私を決して愛さない
BACK INTO ENGLISH
she will never love me
That didn't even make that much sense in English.