Meaning of yī dìng:
一定
surely; certainly; necessarily; given; must
Míngtiān de jùhuì, wǒ yīdìng huì lái.
明天的聚会，我一定会来。
I will surely come to the party tomorrow.
Míngtiān de bǐsài wǒ yídìng huì qù kàn.
明天的比赛我一定会去看。
I will certainly go to watch tomorrow's match.
Kǎoshì de shíhòu nǐ bù yídìng huì jǐnzhāng.
考试的时候你不一定会紧张。
You don't necessarily get nervous during exams.
Tā míngtiān shàngwǔ yídìng huì lái.
他明天上午一定会来。
He will definitely come tomorrow morning.
Nǐ jīntiān xiàwǔ yīdìng yào lái ó.
你今天下午一定要来哦。
You must come this afternoon.
fixed; a certain (extent etc); particular
Wǒmen míngtiān yīdìng huì qù gōngyuán.
我们明天一定会去公园。
We will definitely go to the park tomorrow.
Zhè běn shū duì wǒ de xuéxí bāngzhù yīdìng.
这本书对我的学习帮助一定。
This book definitely helps my learning.
Tā jīntiān de xīnqíng yǒu yīdìng de hǎozhuǎn.
他今天的心情有一定的好转。
His mood has improved to a certain extent today.
