The main character of a time-travel novel might not admit that he had time-traveled for the following reasons: 1. The influence of traditional values: In many cultures, people believe that time and space are closely linked and that transmigration is an immoral or risky act. Therefore, time-travel novels may be influenced by traditional values. The protagonists don't want to be seen as aliens or offend others. 2. Social pressure: In time-travel novels, the protagonist usually has to adapt to the rules and habits of modern society. If the protagonist admitted that he was a transmigrator from the beginning, it might attract unnecessary attention and suspicion, which might affect his survival and actions. 3. Mystery and Curiosity: The transmigrators usually bring some unknown things and experiences. The protagonists may be curious and mysterious, so they don't want to reveal their true identity. 4. Problems of adaptation: Time travel novels usually involve the rules and structure of modern society. The protagonist needs to adapt to these rules and integrate into society. If the protagonist admitted that he was a transmigrator from the beginning, it might make him feel isolated and uncomfortable in society. There may be many reasons why the protagonist doesn't admit that he's transmigrated, but generally speaking, this is a creative strategy that can make the novel more interesting and fascinating.