世界很大能认识也不容易不能成为恋人也仍该感激
[shì jiè hĕn dà néng rèn shī yĕ bù róng yì bù néng chéng wéi liàn rén yĕ réng gāi găn jī]
It expresses appreciation of the chance meetings in life, noting that in a big world it’s already fortunate to have crossed paths, so it's better to be thankful even if the relationship can't progress beyond acquaintance to romance.