Or you could be like Nixon and ask the same person for a date for two years until they relent, in the classic screwball tradition. Only recommended for extraordinary circumstances.
This sort of thing is usually considered harassment.
In the 30s, it was romantic comedy.
I’m aware but that doesn’t make it okay, no matter what the quality of the film(s).
If it leads to a happy relationship I don’t see why not. I don’t see too much of a difference between being persistent and “slowly building a friendship”/“being a nice guy” over a similar period of time so long as there isn’t any violence or psychological harm. At least in the former case, the intentions are clear.