Why couldn’t Anatole tell Tullia about the memory potion? If he could have told her, do you think she would have agreed to it?
Anatole wasn’t sure Tullia would have complied. She seemed to be a person “that marched to her own drummer”. Anatole felt who knew best what should be done.
She might’ve, especially if he told her it would save Pito’s life. But she also could’ve been outraged and stopped him, or did something to alter the outcome of the potion (wrote down the truth for herself to relate to later?).
I think Anatole was not sure what Tullia would do, so he wanted the control of the situation. In my opinion, Anatole thought he knew best and was not concerned what others thought. But maybe if someone is a magician and can make certain things happen then you do believe you are more knowledgable than others?