Tā yǐjīng shì mínghuā yǒu zhǔ, bié zài zhuī tā le.
She's already taken, stop chasing her.
Tips
usage
名花有主 (mínghuā yǒu zhǔ) is the common idiom meaning 'the beauty is already taken' — literally 'the famous flower already has an owner.' 名花 on its own refers to a prized flower, but this colloquial usage is very common.