Just one kiss. Sometimes that is all it takes for a heart to lose its balance. She was keeping herself away from him. She keeps telling herself "romantic relationship between me and him is impossible, we rather remain best friends than hurting each other". But his intuition and his hope, regains her trust and her feelings about the truth. She believes that she is in control of her feelings, but she is not. It's hard to hear the melody of the heart when your thoughts are playing their own songs. And in this case, her thoughts are full of deep sorrow, when her heart has plenty of love to be shared with him.