YOU SAID:
I am not the one who was with her last night
INTO JAPANESE
私は昨夜彼女と一緒にいた人ではない
BACK INTO ENGLISH
I am not the one who was with her last night.
INTO JAPANESE
昨夜彼女と一緒にいたのは私ではありません。
BACK INTO ENGLISH
I was not with her last night.
INTO JAPANESE
私は昨夜彼女と一緒にいなかった。
BACK INTO ENGLISH
I wasn't with her last night.
INTO JAPANESE
私は昨夜彼女と一緒にいませんでした。
BACK INTO ENGLISH
I was not with her last night.
INTO JAPANESE
私は昨夜彼女と一緒にいなかった。
BACK INTO ENGLISH
I wasn't with her last night.
INTO JAPANESE
私は昨夜彼女と一緒にいませんでした。
it is unlikely that this phrase will ever reach equilibrium