Jessica showed unfailing love for her sister Krystal and shared the advice she gave on her sister's relationship with Kai. 

During an interview, Jessica brought up Krystal, saying, "She's like a friend. Soo Jung is mature so we talk a lot. It's hard to meet a true friend in society and have sincere conversations, but since Soo Jung is my family we've become most the dependable colleagues and friends." 

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Jessica, who was then asked if she was aware of her sister's relationship with Kai, answered, "Of course I knew. I gave her advice and told her to be careful about exposing it to the public."