By extension, also hints the half sis isn't naive as she portrays, being at one time Yulin invites FL out on a date and coincidentally, half sis asks her to spend time with her on the same day. FL is ofc choosing Yulin, Father is pissed because she's choosing a man over her family. FL ignores them. Later on, half sis can tell FL and Yulin are close and in the 2nd timeline, gains an interest to Yulin instead of the Prince, much to FL's dismay but FL has yet to realize her feelings still. She intends to befriend Yulin last I read from the spoilers. Yulin ignores her thankfully.