I love Henry's face in this scene - the way you can clearly see every emotion as he finally lets go of that last piece of armour and bares his heart...
And the thing is, Alex has flown across an ocean and stormed a fucking castle just to declare his love in person, despite fully expecting to be rejected.
He's stated, in no uncertain terms, his determination to fight for them, refusing to let anything but Henry himself get in their way.
He's in the midst of bringing one of Henry's most private and treasured fantasies to life, just because he can, because he wants to.
He's proved repeatedly that he's all in and yet, when he takes just a moment to find the right words to express that, it's still enough for Henry to immediately start doubting. Terrified that his own confession is too little, too late. That Alex is still going to leave him...
At least until Alex lifts his head, smiles, and then tells Henry exactly what he needs to hear.