少年不懂少女的悲伤少女不懂少年的忧愁
[shăo nián bù dŏng shăo nǚ de bēi shāng shăo nǚ bù dŏng shăo nián de yōu chóu]
The youth do not understand the sorrow of the opposite gender; this reflects that teenagers often cannot empathize with each other’s emotions, indicating immaturity and lack of understanding of life's depth at that age.