She saw the way he looked at the girl, she saw everything and it made her blood boil. 

"Oh you look beautiful today, Mi Young-ah.", he said  with sincerity. 

"Thanks Yoseob, you don't look bad yourself", she winks at him, flirtatiously.

The girl clenched her fist, it won't be long until she rips the goregous face off of Mi Young's perfect body. She couldn't believe the nerve of these two..yet she envied their relationship the way they make eye contact to one another she envied it. So..this is how the story goes, eh? She was just the annoying girlfriend who tries to ruin their secret and way better relationship...She wasn't the ing princess..she was the antagonist, the overly jealous that Yoseob obviously doesn't want to spend his whole life with.