Responses
I understand why he is lying but I have read up to chapter 43, learned about Asain culture and dated a Korean off and on for years. I get the frustration but not the strong hate over it.
Hajin ended the conversation with Hanwool at the end of this chapter. With how he ended it with Hanwool it shows He already knows

I hate that Hangyum is hiding his real identity from Hajin, lying to his face like that,but at the same time Hajin has skeletons too, but damn can't they just clear the misunderstanding and reunite.Im low-key hoping his twin brother tells Hajin the truth...but what are the chances of that.