"Free for the world"? what kind of answer is that?! If you are interested in someone, it doesn't take much to communicate back even if you "didn't feel well". Its about 10 seconds to send a text.
I don't think it matters a lot if you text or talk or whatever, so long as she feels you are fully confident and sincere.
If she doesn't know you, she has to make a quick decision based on what she does know about you. Is that a quick glance and a text? Put yourself in her shoes... try to understand how she would feel and work with that. If she is aprehensive, make her feel safe. If she is shy, make her feel comfortable. If she is hot and popular, make sure she knows you aren't going to be someone to play around with.
I would be firm and make it clear that I have an interest. But also have value for that interest. If you know you are a good guy and genuine, that interest has value. So don't sell it short. Don't cheapen it. Be clear about it, and if its not received well, then don't let it hang out there for no reason. Pull it back because there are plenty of women that would appreciate it.
I don't mean be a jerk or anything, be nice and polite because thats who you are. Always. But don't pine... don't keep things hanging out there like a little puppy. Let her know that her lack of enthusiasm isn't going to wash with you. You don't need someone that is all willy nilly.
In all my experience I can tell you this. Be firm and to the point. If its not received well or there is hesitation, you be the first to say "thats OK, thank you". That makes a woman question her rather impulsive decision. "what did I just do?"... "did I lose out?".... let her mull that over a bit.
Let her see how great a guy you are in general, always curtious, always polite, always kind to others (even to cats that scratch your car
). Let her question whether she made the right decision or not.
I know this not giving up thing is great enthusiasm, but you aren't riding a bull in a rodeo. Its pretty straightforward. She should take it or leave it, its a limited time offer. You snooze you lose. Any decent girl should at least give you a chance. If she is not willing to do that, then move on. She is not the right one for you.