I feel this movie is about love, but more importantly self-love. Rosalba had to learn how to love herself; how to become a confident, independent woman. With her husband she wasn't appreciated, and she wasn't challenged in her every-day life. As soon as she was left, and decided to hitch a way to Venice, life was put back into her body. She finally had meaning, excitement and motivation for her day other than doing everything her family wants.
During this accidental vacation, Rosalba received a chance to learn what she wants in life. She basically learns that her old life was suppressing her needs and wants. In her marriage, she was being suffocated; she had no voice. Once she starts working at the flower shop and making her own connections in Venice, she realizes that she can make her own decisions. And that she can also be successful on her own. She doesn't need her rude, unfaithful husband.
One of my favorite moments is when her husband asks his mistress to iron some of his shirts. Her reaction was something like, "I'm not your wife!" It's funny how when separated, he finds out how much he needs her, and she finds out how much she doesn't need him.
She ends up becoming happy on her own, though she does miss her children and feels guilty for leaving them. But she also ends up falling or Fernando and re-kindling her love of the accordion.
All in all, Rosalba completes her character development, and it's very rewarding to see such happy ending where she gets everything she deserves. Love, family, happiness and self-worth.