I've been through this manga. I was the dumbass. And the girl I had a thing for liked me, knew I liked her, knew she was way classier than I was, and tried to set a rejection on autopilot so everything could come apart gracefully.
It worked, but it was all nothing at all. Chizuru needs to listen to the other girls and let it go. Otherwise, she'll look back on a smoking crater where she thought a pleasant relationship took place, because it was all for nothing.
Besides, she's got to come to grips with the fact that she's a hooker.