Arthur is quiet for a very long time after Merlin tells him. Their gazes are locked, neither of them able to look away. The silence is so heavy and drawn-out, the stare so intense and unblinking that Merlin wonders whether his magic is slowing down time of its own accord, aware of the hugeness, the finality of this moment. His pulse has sky-rocketed, his heart thudding as fast as a rabbit's; but at the same time there's a strange giddiness beyond the panic, something delighted and freed, and Merlin wonders if this is what truth feels like.
"Are you afraid?" is the first thing Arthur says.
"Should I be?" Merlin asks.
Arthur's hand reaches out, wrapping itself around Merlin's wrist with unexpected gentleness, and Merlin is not afraid.
"Thank you," Arthur says, "for finally telling me."
Merlin understands, and the intensity of the moment takes on an entirely different meaning.
Arthur already knew.
Exactly how long he has known doesn't matter. There's something in the tightness around his eyes, something that speaks of hurt and longing and says, long enough. He knows everything, must have guessed it a while ago, must not be as blind as Merlin hoped he was. His eyes are clear and piercing now as they look at Merlin, and his touch burns against Merlin's skin.
Merlin could apologise, but he doesn't think that would help anything. He could say a thousand things, offer a thousand explanations. They are on the tip of his tongue, but something keeps them from coming out. Because if Arthur knows about the magic, then surely he knows this, as well – that there can be no apology, and that Merlin has no regrets.
"You do trust me," Arthur says, and it's not a question, but he sounds awed, and shattered, and incredulous, and –
"Yes," Merlin says softly, because Arthur needs to hear it.
When their lips touch, it's a gentle, barely-there kiss, just a light pressure on Merlin's mouth, but it is enough to send Merlin's entire world shifting. He feels as though the ground has opened up beneath his feet and he is falling, falling into Arthur. This is about more, so much more than magic; this is a moment that could never have been if Merlin's secret had remained unspoken. Now they can have this, now they can be what they were meant to be.
The kiss is light and open and perfect, and Arthur tastes of truth, and it feels like this, too, has been long in coming.