yí
yī
dìng
dìng
1
surely
2
certainly
3
necessarily
4
fixed
5
a certain (extent etc)
6
given
7
particular
8
must
一定会来的。
He will certainly come.
一定要吃药。
You must have medicine.
没问题!我明天一定会去你家和你们一起过春节。
No problem! I will definitely come to your house tomorrow to celebrate the New Year.
一定会帮我解决问题的。
He surely will help me solve the problem.