The Kiss will happen in Episode 11 (today!). In this episode, Joo Won ups his game and becomes more aggressive in pursuing Ra Im. He confesses his feelings to Ra Im once more and tries to kiss her. Ra Im pushes him away, but he wouldn't let go.
The OTP's prior kisses, "The Bench Kiss" and "The Cappuccino Kiss" happened because of the surrounding circumstances but this time Joo Won deliberately goes to kiss her to determine where his true heart lies. The production unit said that the filming of this third kiss proceeded very naturally and done without any NG.
Forceful? But she doesn't seem that unwilling...
Via OSEN, naver translated by Baidu (chinese)