Why don't you see what's available first... I am big on movies, but if you pick some flighty romance film it's just going to put a sour taste in HER mouth comparing you to some movie star...
I try to be very selective about the films I endorse seeing...
I don't see the harm in the film in general, depending on what it is... Don't take her to some romantic chick flick, you are going to just pale in comparison to some fantasy romance film ...
Why are you two batting around this "i only wanna go if you wanna go" crap...
Why not tell her you want to see x and invite her along... If she says no, you go anyway...