在天愿做比翼鸟，在地愿做连理枝 zàitiānyuànzuòbǐyìniǎozàidìyuànzuòliánlǐzhī wishing for eternal love
Meaning "in the sky we would be two birds flying wing to wing, and on the earth we would be two trees with branches intertwined"; used to express a wish for a couple to remain together forever, in life and death.