Who is the king? God.
Who is the beauty? You.
And what does it mean to be enthralled? That's where this verse really gets good. Webster's dictionary gives three definitions for enthrall.
1. to hold spellbound
2. to hold captive
3. to enslave
The God of the universe is enslaved by your beauty. You captivate Him. Your beauty holds Him spellbound.
Why? Because you are having a good hair day? Because you wear a certain size jeans or manage to temporarily have clear skin? Do you think these powerful words were written because of your ability to ascribe to the version of beauty the world esteems? I don't think so.
God is enthralled by your beauty because He created it. We read in Psalm 139 that He knit every part of you together in your mother's womb and that you were made fearfully and wonderfully.
My greatest desire for you girls is to know that the world's beauty standards are fleeting at best (and destructive at worst). The world may never recognize your beauty at all, but there is one who does. He is a great king. And He is enthralled by you.