What assumptions does Arthur wrongly make about Eel Marsh House in the novel, The Woman in Black?

Eel Marsh House defies Arthur’s expectations. He presumes that the eccentric widow would have left her house in a state of disarray, but the house is actually quite neat and tidy, showing that the woman was not quite so crazy as everyone believed her to be. Arthur is enamored with the beauty of the house and its surrounding marshes. He finds it difficult to believe that the house could be the site of such suffering, illustrating how appearances are often deceiving in the novel.