因为有你才会美因为有你不会黑
[yīn wéi yŏu nĭ cái huì mĕi yīn wéi yŏu nĭ bù huì hēi]
The phrase translates to 'It's beautiful because you are there; it's not dark because you are there'. This nickname expresses an idea of someone brightening another's world and making life meaningful just by being present, counteracting any darkness with beauty.