你是我的忠贞不渝你是我的百里挑一
[nĭ shì wŏ de zhōng zhēn bù yú nĭ shì wŏ de băi lĭ tiăo yī]
It translates directly as 'You are my loyal and steadfast one; You're the best picked from a hundred.' This signifies deep commitment, singling out someone above all else in matters often involving romance.