不朽少年失她失心朽少女失他失命
[bù xiŭ shăo nián shī tā shī xīn xiŭ shăo nǚ shī tā shī mìng]
The undying boy loses her and loses heart, while the undying girl loses him and loses her life. Describes the mutual loss and devastation between two lovers, highlighting their inseparable connection and tragic love story.