What is the significance of fortune telling? _ How to calculate the decline of Yin and Yang

Yin goes in and Yang goes out, which means avoiding separation. What does this sentence mean?

No, if this divination is divided and combined. Is that your relationship must go through twists and turns to show true love. Yin goes in and Yang goes out, night falls and the sun goes down. But after that, dawn will come. Please don't worry, you are Yang, and Yang wants to quit, so you have to be patient and give in before you can get back together.