年轻时候我牵你的手老了以后你牵我的手
[nián qīng shí hòu wŏ qiān nĭ de shŏu lăo le yĭ hòu nĭ qiān wŏ de shŏu]
It can be understood as 'In youth I held your hand, in old age you will hold my hand'. It describes the hope of growing old together with one person you cherish for a lifetime.