(The way you write is genuinely so good and satisfying to read)
Arthur stared at Lucian, his eyes wide and brows slightly raised. Lucian didn't want to marry the Queen's daughter? But why? Was it the Queen's coldness and idea of being a part of her family? Perhaps a fear that her daughter had a similar iciness about her? Arthur, himself, could think of plenty of reasons why he wouldn't want the offer, but— why not Lucian? Unlike Arthur, Lucian had the charisma, the popularity, the charm, the looks— everything one could ask for in the perfect candidate to marry into the royal family. Why would he pass up an opportunity like this? Certainly it wasn't the reaction he'd expected.
An old scene replayed in Arthur's head. Several years ago. Him and his father in a heated exchange over a lady Arthur never loved and never would.
"She's a nice girl, Arthur. Pretty, too. And comes from a good family. And she's interested in you."
"I can't."
"Why the hell not?"
"I don't know." Arthur's voice was calm, empty. "I just can't."
"Then don't marry her," Arthur said, the words rolling off of his tongue, surprising himself. "I'm sure the Queen won't be too happy if you turn down her offer, but we'll wait until after you've rescued the Princess. As cold as she is, surely the Queen won't kill the man who saved her daughter, even if he does turn down the princess' hand in marriage." What was he doing? Advocating for Lucian to turn down a direct offer from the Queen? It was a privilege— an honor— that most people would have given anything to have, and here Arthur was, telling Lucian to decline it? Yes. Apparently so. Whatever it took to get this tangible weight off of Lucian's shoulders.
"It's a big decision, Lucian," Arthur added on. "You'll have the whole journey to think it through. Maybe you will change your mind when you meet the Princess. But if you don't… we'll figure out some sort of solution to convince the Queen not to go through with the marriage arrangement." He said this, partly, to reassure himself that there would surely be an answer to the problem, something that could be done to get Lucian off the hook. It bothered him to think of his friend being pulled into a lifelong arrangement that would only leave him miserable. "But for now, we only have a little time to prepare for our adventure. That much, we can't back out of." He patted Lucian's shoulder in what he hoped was a reassuring manner. "We should focus on one thing at a time, my friend."