When Arwen approached William and talked about him being betrothed to Seraphine, William hadn't even needed to doubt Seraphine for a moment; he was confident that she was completely loyal to him.
He didn't doubt her even for a moment.
But chances were that she might be being forced into this marriage by her mother or maybe the political sphere of the Sylvaris empire, and so William used his omniscient eyes (SSS) talent.
He used the ability to see through lies and checked whether Arwen's words held any speck of truth in them or not. And as expected, his words were complete bullshit.
Strangely, he could see a dark and murky halo around this elf thanks to the omniscient eyes.
Understanding about the halo entered William's mind, and it seemed to be indicating that Arwen's survivability and fate were grim.
William didn't know why, but this guy seemed to be in deep shit somehow since, on the surface, everything looked alright other than him being a jealous suitor of Seraphine.
