Answer:
In my opinion, the phrase means that a person's personality is not as easy to see as we think it is.
Step-by-step explanation:
For example, Say someone seems so nice and calm (Like Malgore). But when something offending is said to him or his family (Like Fellshift saying that his stepdaughter Louisiana is nothing but a mere pet) he becomes mad and insane, his mind filled with bad intentions. Even when nothing is said, Malgore is distrustful and quite off the edge. Even if he seems nice, he may not be what you see on the outside. His personality is not as easy to see as you think.