Her mother depends heavily on others, on the emperor for his favour, on her son who she believes will be the future of the family and on her daughter (the MC) for daily affairs. She isn't a good mother or even a good person really, but I can understand why she is the way she is. She's isn't independent and lives only based on her beauty and reliance on others. This makes her "love" which (which only comes when she needs her for something) towards Artezia rally toxic.