Wilkie Collins 
The Two Destinies [PDF ebook] 

The story takes place during the time period of the author, in the mid to late 1800's in Great Britain. Two young people, one, the son of a British nobleman who was 13, and the daughter of his bailiff, who was 10, are constant companions. Neither have siblings and they live on the estate of the nobleman. They feel they are kindred spirits and meant for each other and the bailiff doesn't do anything to stop the relationship.
The nobleman is away in the United States attending to an investment into which he has sunk all of his funds and also funds of outside investors. The nobleman's wife is not a strong person, and is not preventing the relationship, as she is mainly looking for her son's happiness.
The nobleman's brother hears of what's happened and after unsuccessfully trying to remove his nephew from the property to force him to live on his land and away from the bailiff's daughter, he writes to his brother in the U.S. The brother returns and terminates the employment of his bailiff in very bad terms, but the bailiff's mother, who was from a titled family but married a laborer because it was her true love, prophesies that the two children are meant to be together and no matter what the boy's father does, the two children will end up united.
The bailiff moves away and leaves no trace of where. The nobleman takes his family with him to the U.S., but years later, the investment sours, and all the money is lost, and the nobleman passes away. The mother and young boy who is now a teenager return to the U.K. and they survive on a small amount of money left by her family for her. A wealthy man, who had loved the boy's mother and who is still single, gives the mother an offer of marriage and she accepts.
When the young man, George, is now grown up and 23 years old, the stepfather passes away and asks that for George to inherit the estate, he would have to take the stepfather's last name as his own and he agrees.
The little girl, Mary, 10 years later, is now 20 and, after the death of her father, finds herself approached by a man whose life her father had saved, with an offer of marriage and she accepts.
Both George and Mary meet repeatedly after this, and, because they have each changed in appearance over the years, and each of them have different last names, they don't realize who they are, but they are inexplicably attracted to each other. Mary is exposed to numerous troubles, and George is repeatedly finding himself there to help her, and is hoping, that despite Mary's situation, that she will end up as his wife.