太主动了会掉价太在乎了会心碎
[tài zhŭ dòng le huì diào jià tài zài hū le huì xīn suì]
Meaning 'Being too proactive devalues you; caring too much breaks your heart.' This conveys the caution in not overstepping in personal relationships due to fears of losing value or experiencing heartbreak from being too vulnerable.