你是我深巷透进的阳光
[nĭ shì wŏ shēn xiàng tòu jìn de yáng guāng]
It metaphorically means 'You are the ray of sunshine that penetrates into my life'. It signifies that someone brings brightness, warmth, and hope to another person who may be in a less desirable situation, similar to a narrow alleyway without sunlight until you come into their life.