This is the 266th most frequent Korean word.
반드시
Certainly; absolutely; without fail.
In this sentence, '반드시' indicates the imperative condition or requirement of eating food before taking the medicine.
이 약은 반드시 식사 후에 복용하세요.
Take this medicine necessarily after a meal.
This usage of '반드시' emphasizes the speaker's confidence or guarantee regarding the likelihood of the outcome.
그는 반드시 성공할 것이라고 확신합니다.
I am sure that he will certainly succeed.
Here, '반드시' emphasizes the necessity or obligation of submitting the homework, conveying that it is a crucial and essential action.