姑娘们不懂的忧伤
[gū niáng men bù dŏng de yōu shāng]
Sorrows That Girls Don't Understand. Perhaps suggesting sadness, loneliness or emotional pain that others may not fully comprehend, especially girls in this context. There's also an implied critique towards a certain kind of superficiality or naivety associated with young women's perception in traditional stereotypes.