必定 (bì dìng): Surely / Certainly (Adverb) — Meaning & Stroke Order

Although the prospects seem optimistic, the outcome certainly will not be smooth sailing.

As long as you persist in exercising and maintain a reasonable diet, your physical condition is sure to gradually improve.

Following this plan, the project is bound to succeed.

Don't worry, he will certainly do what he promised; I have confidence in him.