青青子衿悠悠我心但为君故沉吟至今
[qīng qīng zi jīn yōu yōu wŏ xīn dàn wéi jūn gù chén yín zhì jīn]
Taken from ancient Chinese poetry, it means 'Your green collar flutters softly, your image haunts my heart; but because of you I muse and sigh to this day'. It signifies unwavering affection and longing.