I've re-read the whole manwha and it kind of seems that No-rae has never tried anything to develop the relationship beyond the stage of friendship, apart from the known almost-kiss. She even regretted acting in that way.
She does want to remain by the side of Seol-a, being sometimes overprotective and jealous, but doesn't look like she is going to make a move or something, and I don't think she is willing to risk what they have unless she knows for sure what Seol-a feels. We also have that "wall" around her and all the damage done due to the ex, so, this is tough for her, although we don't get to see her POV that much. Seol-a, on the other hand has been suffering so much it just breaks my heart.
She has been flirty since the beginning, we know that, she's much more determined (thank god) than No-rae and probably is going to be the one to confess (as she has tried before, coff coff, that cockblock). But who knows what will happen, my guess: two or three more chapters to get something dense. And I would love to know what No-rae is going trough...
