你要是敢离开我我就废了你
[nĭ yào shì găn lí kāi wŏ wŏ jiù fèi le nĭ]
'If you dare to leave me, I will disable you', conveys threat through strong language and implies a controlling behavior pattern over someone else, suggesting possessiveness bordering on obsessive. This one reflects more about insecurity than actual intentions but it still represents quite a harsh tone overall.