Hmm I don't think Julie was the main objective of Beth deceiving her. If anything it was using her as a tool or bait to get the leads to separate and cause some damage. They have enough information to assume they would need an innocent person to lure FL out alone so they might have a mole inside the castle already. With Julie escaping so fast it's not easy to determine what they were going to do with her next but it might have been possible that they were going to use magic to manipulate her to being one of their pawns or another mole inside since they worked so hard to kidnap her quietly. . . idk but I really like that you picked up translating this, thank you for asking us questions I'm excited to discuss more!