I don't think there are any significant rules in "charming" a Polish girl that would not apply to women of other nationalities.
plus in her vision I am still one foreigner only, of course, she doesn't trust me directly
If you are able to tell who you are in her vision, then you should know if you have chances or not. Unless you're just guessing.
I'm not an expert on relationships, but I can tell that being in a friendzone is not a good thing if you have different expectations. It's harmful to both of you.
PS. I don't know if I understood everything - did you tell her about these feelings you think you have, or not? I'm a bit confused about that middle part, but I doubt that I could give you any valuable advice anyway.