How I understand it is that the friend remembers MC had a lot of guys confess to him in the past (i.e. he "confuses" them lol), then puts 2 and 2 together that him and Jigu were acting close, and Jigu had a strong emotional reaction to something MC did.
Usually strong reactions like the one from Jigu are because a person really cares about you and the way you act toward them. So I think the friend is just kind of concluding on his own because of the two experiences.
yes, i understood the same! i was j wondering if at the end, his reaction of "this crazy bastard (i assume is about yeowoon/mc since yeowoon started going off on jigu). looking at them, it's only a matter of time." implicates yeowoon may have some sort of feelings towards jigu as well, & not only jigu towards yeowoon
i may have forgotten a lot of points because i haven't read this in a while, but does yeowoon's friend notice smth about his behaviour that indicates he's got some feelings for jigu that he hasn't unpacked yet? so far, i personally believe yeowoon's behaviour is j normal, but the way his friend is reacting & his last sentence makes me feel like there's sumn about yeowoon's feelings towards jigu too, & not solely j jigu's towards yeowoon