It's fantasy movie from 70's or 80's or 90's, perhaps from Soviet Union or Czech Republic. My friend saw it in 80's or 90's. The main character is a man (perhaps a young boy).There are three brothers in the film. Their main enemy is an evil wizard. First brother is seduced by the vision of a mass of food. Second brother is seduced by the vision of wealth. Third brother hears the woman's voice. This third brother gets his hands on a sorcerer's heart, which is shaped like a ball and made of slag (or other stone), or at least it has a texture. He breaks the sorcerer's heart. As a reward, he gets half the kingdom and a princess for his wife. His brothers work as punishment in the mill, they turn the windmill.
The wizard lived in a cave and keeps his heart. He doesn't leave a cavern. He is immortal (probably).I think that main weakness of the wizard was his heart and it was reason that wizard keeps own heart. At the end, the main character destroy his heart, when a wizard leaves a grotto. The wizard rides and falls from horse and die (something like heart attack).
It's similar thread like "Captain Sindbad" (1963), but it isn't.
Definitely not:
Kashchey the Immortal, Russian Кащей Бессмертный, 1945 B&W fantasy directed by Alexander Rou, with Georgy Millyar as Koschei.
Fire, Water, and Brass Pipes, Russian Огонь, вода и... медные трубы, Ogon, 1968 fantasy directed by Alexander Rou, with Georgy Millyar as Koschei.
Beloved Beauty, Russian Краса́ ненагля́дная, 1958 stop-animated film.
Sitting on the golden porch (На златом крыльце сидели), 1986 fairy tale directed by Boris Rytsarev
I found very similar thread in "The Firebird" (1997). I watched it and I am sure that evil sorcerer is immortal and his power is hidden in his heart (in a shape of crystal/stone). Main character discoveres truth about weakness of the wizard. Unfortunately, it isn't "my" movie.
I am sure that it was something connected with Koschei or Firebird, but older - 70's or 80's probably.
If you have any suggestions connected with thread, inform me, please,