It is not just a matter of closing the chat or not.

My question is: if a girl hardly know a guy and she is somehow not interested in him (she is single), what could possibly be the problem if she gives it a try and open a communication channel with him to get to know him more, may be she formed a negative first impression about him but that was never the way we judge the personality of someone.

Throughout my life, I formed negative first impressions about some people, by time you realize that these first impressions were never correct.

What might be the problem if she talked with me, this will result in that it has been confirmed that I am not good and then she will easily drop me or that I am good and then she may continue talking to me.

"I do not regret the things I've done, but those I did not do when I had the chance."
Rory Cochrane