Meaning:
Generally speaking, "I give my heart to the moon, but the moon shines on the ditch", which means that I am kind to you, but you are cold and ungrateful. My sincere efforts have not been rewarded and respected.
Source:
A few words of advice to his father in Yuan Dynasty's brilliant Pipa Story-"This tit is rude and will collide with me. My words are not in the right place, son. My husband's words are contrary to my father's. I hate children's knowledge. I should have trusted the moon, but the moon shines on the ditch. "