向日葵的微笑只属于太阳太阳的光芒只照射向日葵
[xiàng rì kuí de wēi xiào zhĭ shŭ yú tài yáng tài yáng de guāng máng zhĭ zhào shè xiàng rì kuí]
The smile of the sunflower belongs only to the sun, and the sunshine only shines on the sunflower. This reflects a loyal relationship, like the undying affection between two lovers or close friends.