What's "how true of you" mean here?

Native speaker’s answer
Rebecca
Here, "how true of you" means that the statement "disguise is always a self-portrait" is true for her. It's accurate and correctly describes her in that she didn't try too hard to be someone else. If something is "true of you," it means that it represents you and your behaviour well. Ex: How true of you to always be positive. Ex: It's true of you to tell others to be kind because you are always kind.