how the novella should have ended?

I suppose this depends on what you are looking for. Steinbeck's novels seldom end happily. It would sound strange for Kino and Juana to live happily ever after with the money from their Pearl. You could have their baby survive and they give up the Pearl; Kino could realize that the Pearl has only brought strife to his life.

kino sold the pearl fulfilled all his dreams and lived happily ever after