William,No matter where you are from an invitation to any woman either married or unmarried for an innocent meal can not be extended unless you both are known to each other .
If you had approached her out of blue how can you expect her to accept your invitation? It would be proper if you build a rapo with her first. Got to know each other. What your background is your education your thinkings and so. and after an initial know how you can extend such an invitation . Then it is just possible that she would accept it, Then also do not reveal your such interest in her at first meeting itself. It will bust it . Just talk with her and tell her how amused you feel in her company . See how she responds and then taking a cue you can proceed further. seduction is an art and it requires a lot of patience. Best of luck!