Behavior can definitely be deciphered to show that how someone acts doesn't actually convey how they are are or actually feel.

When someone is elated and excited, they might do something out of character and behave differently. How you understand that is up to you and your own history/interactions. That person might generally tell you that they aren't actually happy, but their behavior definitely tells otherwise.

Another example would be depression; someone who suffers may behave much differently than they expect (or would like) to be, so much so that most people get mixed messages about how that person might actually be feeling.

I remember once telling my sister that even though we hardly talk, and that sometimes it's impossible for me to even look her in the face, it doesn't mean I don't want to talk with her. It seems odd writing it, but it's true. My behavior might send you a mixed signal, but you might never have taken the time to try and understand the behavior vs the person's actual message (although, most times there is no message, just misunderstanding)

Just trying to gain some clarity on the idea of behavior vs actuality.