She's so naive that she'd believe any lie in her moment of grief. All she knew was that someone murdered her mother and someone threw Bianca's name. This story has you on your toes because yer not sure who the villain is. My money is on the stepmother killing her mother, but not sure who put out an assassin on our girl, maybe the jealous girl who is pinning for the Crown Prince?
I'll just share the link instead; it'll take you right to the spoiler sum up someone gave on the novelupdates forum.
https://www.novelupdatesforum.com/threads/i-may-be-a-villainess-but-i-wont-live-my-life-that-way.189971/#post-7714041

Girl?? On what basis are you accusing her? Because she's a Noble? Wouldn't you think your stepmother would be the prime suspect? Your mom was also sus tbh