There was a flashback revealing that she was the daughter of one of the bandits who attacked Don Ishmael Cardinal, the father of Don Roman. Furthermore, it was because of her father's death that she grew resentful of the Cardinals. To add more fuel to the hate fire, she is actually the sister of Menandro, which makes the bandit a Silverio. Menandro sold Catalina to a rich man, who made her life a living hell. Catalina found love in another man but hid the affair until it was too late for her lover. She gave birth to Dulce and brought her to Menandro in secret so that she can be his child to raise. You can see from this convenient flashback why she feels forced. No one knew about her. We did not even see any indication that Menandro had any other family, to begin with, not even a hint to this origin to be honest.