Why would Victor say to Amanda that she was frightening him?

Victor is incredibly conservative and, though he loves Amanda, clearly wishes that he was able to take care of her the way he believes a man should. Her spirit and "wild" tendencies (for example, planning on being sunburned and wanting to gamble) go against what, in his mind, a proper English lady should want to do. Moreover, Amanda, already becoming bored with her new husband, is allowing herself to relax and speak her mind. She refers to herself as unreliable and strained, believing that she has never been less unrestricted in her feelings and actions than she is now. While Victor is not nearly as sharp as Amanda, he realizes early on that he does not know her very well.