Found this website very recently.  I am a Singaporean Chinese.  I agree that CJW is wonderful in her expressions.  She is very competent in conveying emotions and feelings.  I have seen her in three other Korean TV dramas but I think WLS must be the most demanding as she has to portray what went through Youjin's psyche and thought process.  If it is a play, she could utter her thoughts aloud in soliloquy.  The same goes for her male lead BYJ, I guess.  Both put up a very competent act.  Look forward to more of their shows.