I'm afaid I can't remember much :-/ but hopefully it'll be familiar to somebody. I've looked for it, but I haven't had any look. So here it goes.....
I believe it takes place in the past. There's a girl, and I don't think her family liked her much. And I think there was a stepsister and a creepy guy who wanted the girl.
All girls have some sort of "coming to age" ball thing, when they're of marrying age. The family's put it on, and it seems like a big affair. The girl's family couldn't afford hers because her stepsister? will have hers around the same time.
She ends up staying with a guy for some reason and his mother? (she likes him and they end up together). He ends up giving her dance lessons for her upcoming ball. He did pay for an instructor at first, but he ended up firing him and teaching her himself. After he hears the instructor being a jerk to her and saying she's hopeless.