许你青丝白发何来求鸾曲答
[xŭ nĭ qīng sī bái fā hé lái qiú luán qŭ dá]
'许你青丝白发何来求鸾曲答' expresses an emotional longing and deep promise. It roughly means 'How could I answer you when I once swore to grow old with you?' conveying heartache, unreciprocated love, or lost promises between lovers. Here the 'youthful hair turning white' is often a metaphor for growing old together.