The person speaking is giving information. “I’m the girl”

identifies her s a category or sort of female.

Now you need a referent phrase “from whom”, “who”, “about whom” etc.

In this case the additional information is “you never get just quite what you see”.

The word “just” is irrelevant here and can be omitted; or you can add the word “exactly” to it in place of “quite”.

Then the full sentence would read,

“I’m the sort of girl from whom you never get exactly what you see.”

It’s still mysterious and means the same thing as a deep meaning sentence; it’s just clearer.

Statement by first person speaker

Identifies self as belonging to a category.

Defines category.

Definition denies appearance level empirical data.

Always refer your words back to the physical reality you’re trying to describe.

If that is still hard, state the opposite of the meaning.

Here the opposite is, I suggest, very clear:

“I’m not the sort of girl from whom you get exactly what you see”.

“I’m the girl: you never get just quite what you see.”

I’m the type of girl, that, when you look at me, you never quite get what you see.

In other words, what she looks like isn’t reflective of what is inside of her.

I’m the girl that you never see before