Aslan didn't know whether Howland was aware of it or not. However, the current Roseanne Villiers was clearly totally different from the previous Princess Roseanne Villiers. Starting from the way of talking, acting, and expressing herself, she was very different from before.
Maybe Princess Roseanne used to be a cheerful person and always an adorable little girl to Howland and King Villiers, but for others, Princess Roseanne was a person full of dignity and difficult to approach.
There was no way the real Princess Roseanne would force herself to work out in the morning or ask to marry someone so quickly. He didn't know what blinded Howland, but ordinary people or the servants and maids could feel the two had totally different characters.
