When she saw Kili almost seemingly deny her every word, concern and worry remained on her face. For him and Fili to face Thorin alone, only brought her worry for the three of them combined. As much as she wanted to keep him safe, there was a part of her where Kili would have to figure things out himself. It was partly the reason why he never fully matured in the first place. He lived, what you could say, a very "sheltered" life in the Blue Mountains, a few years after his birth, since Smaug took the Lonely Mountain. Ever since the dragon attacked, as far as the she-elf learned, Dis grew protective of them in Ered Luin, becoming wary and cautious for their safety, if they ever chose to go exploring at night. 

From that moment on, Dis sealed them and herself inside their home, away from the outside world. But as they grew older, they were determined to see their precious "Delva", once the gifts started to come. Through those years, Saeril was always out there, watching them grow and smile. Yet, here they were; face-to-face, hand-to-hand. 

The she-elf understood him, though, remembering what she just recently thought of, he would have full-reign. He choses, she obeys. With that afterthought, she finally, and reluctantly nodded. She'll hang back, but she will listen in. Closing her eyes, she responded softly. "Very well. Remember the warning, Kili. Something bad is upon us".