How do I know a girl is actually into me?

[Pound]

Ok so i talk to this girl on facebook all the time, almost constantly. We joke around about hooking up and having sex but I cant tell if shes serious or not. Some times she seems serious and then other times she seems to be completely joking about it. I've known her for a few years and we've hung out before so its not like shes a stranger. She said she wants to hang out and drink and watch movies or do something like that. She gets like kinky sometimes but then will be serious too. I dont know what to do. Should i try to make a move? And if i do how do i know when?

[sunny]

Keep doing what you're doing, it seems to be working.

[Karen]

Well you need to show her whos in control because otherwise this wont go anywhere. Treat her kinky ways and flirting seriously, weather she's joking or not and show her what your really made out of... Girls like guys who can be in control

[Mabe]

You won't be asking yourself, or anyone else, this question.

[REZA]

Your first move will be hanging out, movies, drinks, etc.
After that, Time, and of course your heart, tell what your next move will be.