Her: Hey, let me get your number?
Me: Sure - send me your number and I'll text it to ya
Her: Oh, um... I don't want to give out my number just yet
Me: Ah, gotcha - well, hit me up when you're ready to do so
Bottom line: if a girl is not trying to give you the number, she's already OUT. And if they ever give me the excuse of "oh, but I don't really know you yet and want to be safe," I give them the same response back so they realize how dumb they sound.