How can gandalf know things about Bilbo that Bilbo doesn't know?

Gandalf possesses a deep understanding of the nature of individuals and their potential, often drawing on his wisdom and experience as a powerful wizard. He can see qualities in Bilbo—such as courage and resourcefulness—that Bilbo himself may not recognize. Additionally, Gandalf's knowledge of the larger world and its history allows him to perceive how Bilbo's actions and choices could have significant consequences, even if Bilbo is unaware of them. This insight enables Gandalf to guide Bilbo on his journey of self-discovery.