Oh, Yi Gyung likes Bong Won, that's for sure (and it is mutual, actually?)... but I think she is relatively confused as to how close she wants him to be. There's the whole thing that he is immortal, and that, even if they become an item, he would still outlive her (considering that it seems like converting a human into a vampire is a crime in that neighborhood, remember that he was beaten up for converting Ho Seon).
This is just my guess, but I feel like Yi Gyung feels like she is living in the shadow of Jeong Mi. Not only because she is the first human living in that neighborhood since the Ho Seon incident (or her living in the appartment where the kidnapping happened, the first time she moved in), but I feel like it is implied that Jeong Mi would have been in a similar infatuation position as her with Bong Won?