NYDailyNews.com — ?Sin City: A Dame to Kill for? actress Jamie Chung isn?t worried that her ?Rudderless? co-star Selena Gomez appears to be on the mend with superbrat Justin Bieber. ?She has a good head on her shoulders. She comes from a really good family,? says the 31-year-old actress, who worked with Gomez when the former Disney star was 15. ?In terms of her personal decisions, you can?t tell someone what to do. They?re going to discover that on their own. I have faith that she?ll be just fine. I know who she is and she?s a really great girl.?