Rose trusted Jack!!! She lived at a time when women really didn't have many rights and Cal certainly reminded her of that, I mean she couldn't order the food she liked, or smoke, ect. Jack changed her life; he paid attention to her and gave her the freedom she would never had with Cal. I believe her heart was truly with Jack. All of those accomplishments framed on her headboard, at the end of the movie, were possible because of Jack. He showed her how to be free and that nothing was out of her reached if she wanted bad enough. He treated her as his equal, not as an inferior object. He loved her for who she was. To answer the question, it all started with Jack, and she very well might not have had the life that she did if it had not been for Jack. She would have either killed herself or been unhappy the rest of her days or at least until Cal shot himself.