The whole sentence means: it rains in the east at sunrise and rains in the west at sunset, saying that it is sunny. The original sentence is from Liu Yuxi's two Zhuzhi Ci poems. The first poem is about the mood of a girl immersed in her first love.
She loves someone, but she has never really understood their attitude. She has both hope and doubt. I am both happy and worried. The poet successfully expressed this subtle and complicated psychology in a girlish tone.