Romance movie, I believe. The begining started with an old woman with alot of purple or blue makeup on sitting in a mansion. She wore alot of jewelry/nice clothes I believe. A boy stumbles and she offers him a job to have playdated with her daughter/granddaugther. They could have been maybe 10 years old. I think he already knew her and had a crush om her. They end up falling in love later on but had to break it off. The details are a little fuzzy after that, I believe the grandmother bought all of the boys artwork amd he became famous. But his art wasn’t that great. He even had enough money to have a huge apartment. I think either the man and woman got back together or she only wanted him for him for his money? Something about a gun/breifcase and a fire escape? Not quite sure. I just remember thinking about this movie for along time afterwards because it was alot. Oh and the grandmother might have left everything to him instead of the girl?
I might be wrong but your description makes me think of Great Expectations.