宋康王舍人韩凭，娶妻何氏，美。康王夺之。凭怨，王囚之，沦为城旦（秦汉时的一种刑罚）。妻密遗凭书，谬（缭绕曲折之意）其辞曰：“其雨淫淫，河大水深，日出当心。”即而王得其书，以示左右，左右莫解其意。臣苏贺对曰：“其雨淫淫，言愁且思也；河大水深，不得往来也；日出当心，心有死志也。”俄而（不久）凭乃自杀。
Han Ping, steward to Prince Kang of Song, married a beautiful daughter of the He family. But the Prince took her away from him. When he protested, he was imprisoned and sentenced to hard labour on the city wall. Then his wife secretly wrote to him to say:

Rain, ceaseless rain,
Great the river, deep the water,
Yet there is sunrise in my heart.

This letter fell into the hands of the prince, who showed it to his followers, but no one could make out its meaning. Then the minister Su He said:” ceaseless rain hints her sadness and thirsty of love; deep water implies their separation; sunrise in heart indicates her intention of death.” Soon, Han Ping committed suicide.

其妻乃阴腐其衣（暗中腐蚀她的衣服）。王与之登台，妻遂自投台；左右揽之，衣不中手（衣服经不住手拉）而死。遗书于带曰：“王利其生，妾利其死，愿以尸骨，赐凭合葬！”
Han’s wife damaged her clothes secretly. One day the prince mounted a platform with her, she threw herself from the top; and when the prince followers tried to seized her, her clothes tore away and she was dashed to death. On her belt she had left this message:” Your Highness wishes me to live, but your servant chose to die. Please bury me together with Han Ping.”

王怒，弗听，使里人埋之，冢相望也。王曰：“尔夫妇相爱不已，若能使冢合，则吾弗阻也。”宿昔之间，便有大梓木生于二冢之端，旬日而大盈抱。屈体相就，根交于下，枝错于上。又有鸳鸯，雌雄各一，恒栖数上，晨夕不去，交颈悲鸣，音声感人。宋人哀之，遂号其木曰“相思树”。相思之名，起于此也。南人谓此禽即韩凭夫妇之精魂。
今睢阳有韩凭城。其歌谣至今犹存。
The prince was very angry and refused her request, ordering the local people to bury her in a separate grave.
“You two have endless love,” said the prince. “If you can make these tombs come together, I will not stand in your way.”
Then within one day two great catalpa trees sprang up above the two graves. In ten days they grew to an enormous size, and their branches inclined towards each other, their roots intertwined together beneath the soil, and their twigs interwove above. And two love birds, one male and one female, stayed on these trees, not departing day or night. They billed and cooed most plaintively, and utter heart-rending cries. The people of Song lamented the lovers’ deaths and named this tree “the tree of love”. The southerners say the birds are the spirits of Han Ping and his wife. In Suiyang today there is a town called Han Ping, and people still sing the folk song of the lovers.