You said that Clemincine was her bully but is now her business partner. How did they get from being enemies to being friends? Did they have a talk about it, or did they just decide to pretend it never happened?
Corrie has a relationships tab with some basic info on the most important ones.
Vaerii leaving baby Corentine and Corrie's dad and running off was fine. Corentine didn't hate her at that point, she'd just grown up without a mother, but she had plenty of other people she cared about. It wasn't until Vaerii returned to Zephyr's Rest and knocked on their door when Corentine was 15 that that hatred started growing. Vaerii just came into their home and crashed on their couch, ignoring the fact that Mikael was still in love with her. She was taking advantage of Mikael, and Corrie didn't like it. But then Vaerii set her sights on Corentine. She spoke kindly to her daughter and taught her about the magic Corrie had inherited. She went out to buy Corentine clothes, saying she needed to make up for lost time. She praised Corentine's school work, was making them food, bought things for the household. Corentine let her guard down. She hadn't missed having a mom, but now she did have one and it made her life just a little bit fuller and happier.
Vaerii then changed. She started becoming demanding and controlling, nothing Mikael and Corentine could do was right. She turned cold and distant, and left them floundering. Then they came home to find the house emptied. Vaerii had taken every item worth something, pawned it off, and left the island. She'd just used them to fund a place to crash, and then used their items to fund her next travels.
Mikael was broken by this. He didn't put it on her to fix, but Corentine still saw it. She still heard him crying at night and watched him struggle to rebuild their home and life together. Vaerii is someone Corentine could never forgive.