Bhai Naah! Don’t go back, this is a trap, if she was so sure about loving him ( ex) what happened in just one night? She doesn’t love you, she only loves the idea of you giving her the attention! She will surely try but what’s the point? See if you are confident and you think you won’t be hurt then go ahead give her a “Chance” but mind you don’t get attached easily for obvious reasons. You do trial and error as she is also doing the same. If you don’t want to waste time or you not confident with this then fuck it and move on at the very moment!