烟花易冷情意真不忘誓言心愿等
[yān huā yì lĕng qíng yì zhēn bù wàng shì yán xīn yuàn dĕng]
This username implies that even though beautiful moments (like fireworks) fade quickly, true feelings remain and one does not forget promises or wishes made. It conveys deep affection and devotion.