待我长发及腰勒死你待我事业有成抛弃你
[dài wŏ zhăng fā jí yāo lè sĭ nĭ dài wŏ shì yè yŏu chéng pāo qì nĭ]
It implies that when I grow my hair long enough to reach my waist (implying the right time has come), I'll strangle you with it or if/when my career becomes successful, then I will abandon you; it's usually meant to be an exaggerated phrase to emphasize frustration or dissatisfaction.