A few minutes after talking to Benson, Vicente was facing Newton.
As he had already told Rory and Eve earlier, he had revealed the truth to that professor about him actually being Cesar Mazzanti.
Newton already had some suspicions, and thinking about it for a few moments, he could see that it made total sense. After seeing Vicente's current configuration of pentagrams and how strong this young man had become, there was no doubt left in this genius's mind.
He didn't take it badly that Vicente had kept it from him. Like Benson, Newton understood that Vice had a sister to protect and would do everything in his power to ensure that.
It wasn't his or anyone else's right to demand things of Vice!
So he was fine but also happy to finally discover the truth and see Cesar's, or rather Vicente's, growth more closely.