你在我左边第四根肋骨里
[nĭ zài wŏ zuŏ biān dì sì gēn lèi gú lĭ]
'You're in my fourth rib from the left' poetically refers to the mythological origin story of Adam’s rib, conveying intimate attachment and connection. Here, it romantically signifies an individual’s crucial role in each other’s hearts, likened to an integral part such as one's ribs protecting vital organs.