Hmm would have to disagree on these points.
Sure Yona and Hak were being stupid, but Soo-Won is the master of manipulation, who had rendered several characters stupid in this manga because of the same. It's only now that Yona is able to catch on a little and give it back in some ways.
He pretended to be an airhead sometimes, and even showed signs of liking Yona - like giving that hairpin who only people who LIKE someone else give, blushing when Yona said he likes him (yes I know we have been through this argument, and you guys say it's because of his inexperience in love, I don't think so).
http://mangafox.la/manga/akatsuki_no_yona/v01/c001/47.html
http://mangafox.la/manga/akatsuki_no_yona/v01/c001/49.html
Her looking like a woman bothers him apparently. And he would be nervous to fall asleep...what in the world is Yona supposed to think in this case?
Honestly, he was leading Yona on quite a bit, whether intentional or not, we will only know in the end (for example, if Yona didn't see Il's death would Soo-Won marry Yona?)
Stuff like this for example:
http://mangafox.la/manga/akatsuki_no_yona/v01/c001/54.html
Like? Stop being like that and complimenting her hair and showing obvious signs of courting. What else was poor Yona supposed to think? She was never the brightest cookie in the bunch in those days.
http://mangafox.la/manga/akatsuki_no_yona/v01/c001/50.html
Please note...he NEVER flat out refused her. Straight after this confession he gives her a hairpin lol.
Just think of it this way, your friend who you trust and behaves in a way that makes you believe they like your other friend....it's obvious that you would tease them are try to pair them up. You just want their happiness. Soo-Won did deny it, but in a half-serious way in my opinion, and all his actions were saying otherwise. Best friends nag and tease, it's basically what they do when it comes to relationships. It's not Hak's fault that Soo-Won rarely spoke the truth properly to him, or had a big invisible wall around him. Hak just wanted both Soo-Won and Yona's happiness. But what both Hak and Yona got was betrayal. Hak basically idiolized a lie because that was what Soo-Won made him believe.
In real life people like Soo-Won, in my opinion, are seriously the worst, people with two faces. But as a king it works really well and its what Kouka needs. Plus I feel like he is is changing as a person and becoming better too. I want Lily to seal the deal and change him into a decent person forever.
Though it would be interesting for Hak and Yona to discuss about Soo-Won and what they thought of him, versus what happened and what they should do now.