The realizations have begun! Yifan's sense of safety and coziness around Sangyan speaks volume considering her terrible past experiences with men, which is the reason why she did not like Mu guy touching her (also Mu guy is a creep so... that explains it as well). Her subconscious literally equates Sangyan to the Sun and his caring acts towards her remind her of her dad because other than with him, she only felt that she was cared for when her dad was alive.
Sangyan is the embodiment of her definition of love— "I believe what matters is sincerity. Just like a first love, pure and sweet, with a heart that only wants to bring joy to the other person, without expecting anything in return." His acts of service and care are done solely because he wants to do them and not because he desires something in return, which is why many of his such acts remain unknown to Yifan. He beat those goons and searched for hidden cameras in her room, he sat outside the hotel all night and prevented other people from renting a room beside hers so she could practice without any disturbances, he put stick-on safety cushions on the furniture so she doesn't hurt herself while sleepwalking (he did it quietly, never told her once about it and she only got to know of it when she saw it herself) and he always does little things like making breakfast for her, buying her food, having her cover herself with the umbrella properly in guise of the umbrella obstructing his view; he has never once told her he is doing these things explicitly for her except the time when he bought her chicken soup and he did it because he knew that it was her father's death anniversary and she needed to hear that the soup was specially for her. Sangyan's love reminds me of the lyric "all these people think that love's for show, but I would die for you in secret".
He only wants her to live happily just like how she wants him to be happy. She broke both of their hearts because she wanted him to find happiness believing that she couldn't give it to him, while he also always wished for happiness for her even though he was hurt by her words and her backing out on the promise they made to each other.
So, to answer her question "Do I still have feelings for him?"— Yes, she does. She actually never got over him just like he never got over her. It's just that her feeling of guilt towards him and thoughts of not being worthy of him had overpowered her romantic feelings for him all these years. He is special to her and has always been.
