Let's try to recap then:
Ci sta
* as in
A: Ho incontrato Carla ieri, che bella ragazza. - I met Carla yesterday, what a gorgeous girl.
B: Oh sì è bella ma se provi a darle un appuntamento lei non ci sta. - Yeah, she's amazing but if you try to ask her out she sure as hell will turn down your proposal
*as in
A: Ho incontrato Carla ieri, che bella ragazza, la prossima volta le faccio la proposta indecente

- I met Carla yesterday, what a gorgeous girl, next time I'm going to ask her to come to bed with me

B: Sei pazzo?, non ci sta sicuramente- are you crazy, she will surely turn down tour stupid proposal
In this case (non) ci sta means she will (not) have sex with you
* as in ci sta = c'è, this is the easiest case as you can translate it as if you were translating c'è, there is
* as in
Una bella pizza ci sta proprio adesso, sono affamato - a big pizza would do now, I'm veeeery hungry
* as in
A: io vado al cinema, chi viene con me? - I'm going to the cinema, who is coming with me?
B: io ci sto, chi altri? - I'm coming, who else is coming?
* as in a poker match
A: Io punto 100$, chi vede? I bet 100$, who's calling my bet?
B: Io ci sto - I call
Did I miss something?