你的昨天我来不及参与你的未来我定奉陪到底
[nĭ de zuó tiān wŏ lái bù jí cān yŭ nĭ de wèi lái wŏ dìng fèng péi dào dĭ]
Conveying regret ('Your past I could not be part of') but promising commitment to the future ('your future, I will stay with you'). This signifies readiness to support the other person regardless of prior circumstances or history. It shows deep commitment but acknowledges missed chances in the past.