弱水三千只取一瓢饮琉璃一世唯她一人爱
[ruò shuĭ sān qiān zhĭ qŭ yī piáo yĭn liú lí yī shì wéi tā yī rén ài]
This phrase uses an idiom 'Weak water as wide as it is, one only fetches a gourd from it' which means among so many options or choices, one chooses only what truly belongs to them. Here, it specifically indicates loyalty in love for one's beloved partner.