Yukino Miyazawa is currently the most important person in Arima's life. She is the person who convinces him to stop pretending to be perfect, gives him the feeling of self-worth that he so desperately needs and acts as his pillar of support.

Upon their first meeting Yukino is conceited underneath but the epitome of perfection on the surface. Arima is attracted to her, but is rejected when he first declares his love. Even after they become friends it takes quite some time for her to tell him that she feels the same way (the serial of events in which she tried were quite hilarious and also led the poor girl to realise just how little she knows about relationships ^^;). Although he discovers that Yukino is in actual fact quite a strange girl he still retains his feelings for her. He even blackmails her by saying he'll disclose her secret to the rest of the school in an effort to find ways to spend more time with her. Yukino was, in the end, furious enough to walk out on him and consent to allowing her carefully cultivated mask to drop and Arima confesses.

The pair make a delightfully cute couple. They take their troubles together and miss each other desperately when Arima leaves for a Kendo tournament. They no longer maintain the facade of being perfect and try to show their real selves together.