Your OC had ended up running into the princess herself on the streets. Though it may seem like a coincidence, it was perfectly planned for her. She invites them back to her palace, and she has the staff make the both of them dinner.
When they're alone, she begins with a statement, "As you might be aware, the prince and I are getting a divorce. I BEGGED him to stay, just for the sake of our daughter, but he just wants to see the both of us suffer financially. He doesn't even care about her. I raised her as my own, and I love her dearly... I would hate to see a monster like that ruin our family..." Your OC's drink arrives, before she continues, "So, I want to arrange something for you to do. And I will pay you back for this. It's just for the best and for my daughter... Please understand that this stays between us."