I think that Norae wish that Seola don't left her alone with her ex boyfriend. To this she was thoughtful, Ssamba put a lot of emphasis to the message of Seola, "so you do". It has already happened in other circumstances, both when they see one with a boy become insecure and they never know what to do. To the amusement park you remember? Norae went to recover Seola among the boys that the importuning her.
For Norae already hard to see how she feels about Seola, plus it's unimaginable that a beautiful girl like Seola, with a long list of ex-boyfriends, may have romantic feelings for her. And Seola too, when she was about to make the first move, the former boyfriend of Norae threw her insecurity because Seola think that Norae still have feelings for him (mistakenly).
I too would like that their relationship grows a bit and no end how many yuri manga at last page with the first kiss and the rest to the imagination.
Ssamba please, no ...