Abstract: Jiushi (exactly) serves as a high-frequency agreement response marker in spoken modern Chinese language. The word predominantly occurs in two distinct sequence environments: the reinforcing agreement sequence and the supporting agreement sequence. In these contexts, it embodies a semantic of conformity-based reinforcing agreement. This usage presupposes alignment between the speaker’s and the listener’s expectations, thereby expressing strong agreement. The study reveals that such agreement expressions are the manifestation of epistemic authority. The epistemic authority constitutes a crucial motivating factor as jiushi signals the speaker’s elevated epistemic stance. Notably, variations such as jiushi jiushi (You’re so right!), jiushi a (Precisely!), jiushi ya (Absolutely!), and jiushi ma (I told you so!) further diversify the pragmatic effects of agreement expressions.