Kyungsoo needed to tell Jongin the truth. In doing so, he found himself looking at Jongin's eyes like it was the first time. 

Everybody needs assurance, especially Do Kyungsoo. 

Kyungsoo and Jongin both depended on each other. Being orphans, both of them learned at a very young age that life is not what they think it is. But as the time goes by both of them discovered something which gave them the will to hold on and conquer the challenges their life gave them.