Okay i might sound crazy but...he was treated very kindly and was loved by the lize aka author. Because he was the main lead that the author was chasing after so ofc she would treat him nicely and not show her bad side. Plus he grew up with her and never showed her bad side.
when Edith appeared, obv he would be suspicious since she came feom a rival family... And he loved Lize a lot so her blaming Edith would make sense to him since she's a rival AND Lize accused her without him knowing the truth. He's confused why the person he loved suddenly changed and the author never justified who she was like Edith did to Killian.
He's just lost because he'a confused of what is false and true leading him into depression and anger.
Oh and this is my opinion! I enjoy doing an analysis on characters, this was based off the early chapters too! 👍