She's all contained fire and passion. Harry can see it from the moment they meet. A girl in a boys club, she's tougher than nails and harder to get through than a wall of steel. Even then, she's the first to introduce herself when Harry walks into their common space.
She talks him down from the inevitable beating of a lifetime Charlie deserves with eerily practiced ease. It's a puzzle that fits into place. She always knows the right thing to say, at the right time.
It works both ways too. When they're tens of thousands of meters in the air, the tiniest voice he's ever heard from her, "I don't think I can do this, Harry." Charlie being a prick is the only thing that could shock Harry from the impossibility that is Fleur Delacour, afraid.
But it's natural, more natural than anything he's done before to talk her up to making that jump. And even when they're inches from the ground, holding on for dear life and their roles right themselves, him afraid and her fearlessly guiding them to perfectly land in the kingsman shaped circle.
She has his back and he's got hers. Forever