The character of Adele Ratignolle provides a foil for Edna, the story's protagonist. Unlike Edna, she is completely devoted to her children and her husband, enjoying her station in life. Opposites do, however, attract, and Madame Ratignolle befriends Edna and takes the woman under her wing.
Madame Ratignolle understands Edna because she can see how Edna is so different from herself. She knows that Edna's background is not Creole, and that, therefore, she may not understand the customs and culture around her. She is afraid that Edna will take Robert's advances seriously, and speaks to Robert about this, not realizing that he is, in fact, serious. After her labor, she tells Edna to "remember the children (p111)." Whether she knew of Edna's affairs with Arobin and Robert is unclear, but this instance is one example of how Madame Ratignolle tries to be the voice of reason in Edna's life. She possesses a very sweet, maternal nature that Edna loves and appreciates, even when the two do not agree.
On the beach, Edna confides in Madame Ratignolle that she "would give her life for her children, but she would not give herself (p18)." Madame Ratignolle does not understand the difference, but I believe that what Edna means is that she could never pretend to be something she for anyone, not even her own children. She could bring herself to sacrifice anything but who she truly is.