信誓旦旦到尽如梦空
[xìn shì dàn dàn dào jĭn rú mèng kōng]
The meaning conveyed here goes from making sincere promises and declarations that all end up being like an empty dream, highlighting disillusionment or broken vows. It can express regret over unfulfilled words or reflect disappointment in situations that have ended badly despite hopeful beginnings.