一生只爱一个人乀一世只怀一种愁乀
[yī shēng zhĭ ài yī gè rén fú yī shì zhĭ huái yī zhŏng chóu fú]
Expresses loyalty in love, dedicating all their lifetime's affection and commitment to just one person. 'Only one kind of sorrow' indicates that they are emotionally dedicated and experience a singular type of melancholy or pain connected with that unique love story.