AdverbsHSK 3

Expressing "certainly" or "definitely" with 一定

一定 is an adverb placed before a verb to mean "certainly" or "definitely."

As an adjective, 一定 describes something that is fixed or given.

Structure

Subject + 一定 + Verb

Used to express certainty about a future action or strong intention.

一定 + 的 + Noun

As an adjective meaning "fixed" or "given."

我明天一定会来找你。
Wǒ míng tiān yí dìng huì lái zhǎo nǐ.
I will definitely come find you tomorrow.
他一定不知道这件事。
Tā yí dìng bù zhī dào zhè jiàn shì.
He must not know about this.
你一定要好好休息。
Nǐ yí dìng yào hǎo hǎo xiū xi.
You must rest well.
我们一定能完成任务。
Wǒ men yí dìng néng wán chéng rèn wu.
We will certainly be able to finish the task.
他有一定的经济基础。
Tā yǒu yí dìng de jīng jì jī chǔ.
He has a certain (fixed) financial foundation.