So, if he simply wants to "calculate" Ravenna, it's not that difficult.
Although she can see through Ansel's schemes and tricks most of the time, as long as she is subjected to enough terrifying pressure, and always puts things that can affect her ideals on the other end of the scale, even if Ravenna has the ability to see through Ansel's schemes, she will step into the trap without hesitation.
Just like three years ago, as long as Ansel tempted Ravenna with new ideas, she would always choose to submit to Ansel.
For many insignificant calculations, even if they are seen through, it doesn't matter, Ansel doesn't care.
However, even if Ravenna is to some extent easier to fall into his trap than Seraphina, it does not mean that she is easier to tame than Seraphina.
"What can't I accept?" Ravenna said indifferently, "If you fail, you have to bear the consequences. It's only natural."
—Just as her answer is obvious.