Danielle and Rodmilla's relationship is one of the biggest in the film. Danielle's mother died before she could get to know her, so Rodmilla was the only mother Danielle ever knew. Unfortunately for Danielle, Rodmilla couldn't get past her jealousy and bitterness towards Danielle to love her like one of her daughters. Because of this, Rodmilla fits the wicked stepmother role perfectly in Cinderella.
After Danielle's father died, Rodmilla made Danielle a servant in her own home. While her daughters (especially Marguerite) got the best in the world, Danielle was dressed in an old blue dress, and made to do chores around the house. Danielle did everything Rodmilla asked her to do without complaint, expecting just one thing in return. She wanted the love of a parent.
It's fairly obvious Danielle wanted a mother figure out of Rodmilla. She tried everything she could to make Rodmilla love her, from doing all of her chores and waiting on Rodmilla, Marguerite, and Jacqueline, to thinking of ways to please Rodmilla. Danielle even told her that sometimes when she's alone she sits and tries to think of what else she could do, and how she should act. Nothing Danielle ever did was enough for Rodmilla, though. Rodmilla would even tease her with motherly care, asking what she could do to make Danielle try, and telling her she sees so much of her father in her. Danielle fell for it time and time again, just to get hurt. Despite all of the bad things Rodmilla did to Danielle and the things Danielle felt wasn't right, like chasing royalty by trying to get the prince to fall for Marguerite, Danielle continued being nice to Rodmilla. I think she still expected Rodmilla to love her like a daughter.
It wasn't until after the ball that Danielle started to accept that she would never be loved by Rodmilla. I guess she had had enough cruelty. It was then that she learned what she was to Rodmilla - a problem and inconvenience. Like Rodmilla put it herself, Danielle was a pebble in her shoe.
Was there a time, even in its smallest measurement that you loved me at all?
How can anyone love a pebble in their shoe?
I think Rodmilla's dislike of Danielle and her eventual cruelty stemmed from jealousy. At the beginning of the film when her new husband Auguste was dying from a stroke, Rodmilla was on one side of him and Danielle was on the other. Auguste just merely looked at Rodmilla, but then turned his gaze and attention toward Danielle, letting her know how much he loved her before he died. Rodmilla knew Danielle was Auguste's world, and I think she was jealous of that.
Jealousy aside, I think Rodmilla could have also resented Danielle for her new life. When Auguste died, Rodmilla yelled, "Do not leave me here! Do not leave me here!" Pierre le Pieu later said in the film that their soil was some of the best in the province, but poorly tended. I think that's because Rodmilla never intended on being a farmer. She tried everything she could to get back to court, apparent from her struggles to make her daughter Queen. Auguste's death left her alone in a place she didn't want to be with a new daughter to take care of. It's easy to imagine she didn't care for Danielle because of that.
When you think of all that Rodmilla did to Danielle, it's hard to see how Danielle could have any compassion for Rodmilla at all. She made her a servant, witheld love from her, beat her, publicly humiliated her at the ball by outing her to the man she loved, sold a man Danielle considered family, sold all of her father's belongings, was going to give Marguerite her mother's dress, let Marguerite burn her father's book, and sold Danielle to an older man that sexually harassed her. Despite all of her cruelties, though, Danielle didn't let Rodmilla and Marguerite sail for the Americas.
After Danielle and Henry married, the King and Queen called Rodmilla and Marguerite out for lying to the Queen, an offense that was punishable by death. The Queen stripped them of their titles and was going to sell them to the new colonies unless someone there would speak for them. Danielle only asked that the King and Queen show Rodmilla and Marguerite the same curtesies that Rodmilla and Marguerite showed her.
I want you to know that I will forget you after this moment and never think of you again. But you, I am quite certain will think about me every single day for the rest of your life.
Rodmilla and Marguerite became servants at the palace.