你是我心中开的最美的花儿
[nĭ shì wŏ xīn zhōng kāi de zuì mĕi de huā ér]
Which translates into 'You are the most beautiful flower in my heart.' Just as it appears, this sentence expresses admiration and affection. Someone could use this kind of nickname because the recipient brings warmth and vitality like flowers blooming in their heart. Thus, it shows a profound love and adoration.