She said the pig will grow and that Elya will get stronger
Madame Zeroni tells Elya, that on Myra's birthday, he has to carry Zeroni up the mountain. If he doesn't, all his decendents will be doomed for eternity.
Elya takes the piglet up the mountain everyday. It gets bigger and fatter. Elya gets stronger.
On Myra's birthday, instead of carrying Madame Zeroni up the hill, he has a bath.
Elya takes his pig to Myra's house. So does Igor. Both pigs weigh the exact same.
Because both pigs weighed the same, Myra's father let her pick who she would like to marry. She couldn't choose, so she tells the boys to pick a number between 1 and 10. Igor says 10. Elya realises that Myra has no feeling for him whatsoever, and says to marry Igor.