I'm an ENFP woman and I use to do this before I was married. If I liked a guy, I would play hard to get but if he played hard to get I would chase him even more. However, As a ENFP sagittarius, I tend to flirt period. So if this girl is coming up with an excuse as why not to hang out she is probably not into you. I was usually up for anything, always wanting to hang out and meet new people when I was single. If I got intimidated, I might put up a front like you are saying. If she thinks you are really good looking, she might not know how to act around you and is nervous or distant, "playing it cool". However, I have had guy friends who liked me and even though I loved being around them, I never wanted to tell them, "Hey, I don't like you". So she might be flirting to be nice because ENFP's are extremely social.