I don't know who you are..
How your face looks like..
Your flaws..
Rather the whole in you..
Basically, I don't know anything about you..

But;

You don't know how much I want you to be mine..
How much I endear you..
How I long for you..
To be in my arms..
And I to be in your heart..

It is just; I don't know who you are..