V-기로 하다/했다 grammar = decided to, promised to ~make a promise or decision

V-기로 하다 grammar = decided to, promised to ~make a promise or decision with oneself or someone

Usage:

- Express a promise or decision with oneself or someone = decided to, promised to…

- The grammar is mainly ended in the past tense -기로 했어요/했습니다. 

- It is also ended in the present tense -기로 해요 to express that the speaker and listener make a promise to do something = -기로 합시다 (do something together)

Verb + 기로 했다 = decided to, promised to

가다 → 가기로 했다 (decided to go)

만나다 → 만나기로 했다 (decided to meet)

놀다 → 놀기로 했다 (promised to play)

돕다 → 돕기로 했다 (promised to help)

듣다 → 듣기로 했다 (decided to listen)

여행하다 → 여행하기로 했다 (decided to travel)

Examples

1. 건강 때문에 올해부터 담배를 끊기로 했어요.

I made the decision to stop smoking for my health from this year.

2. 주말에 친구하고 같이 영화관에 가기로 했어요.

I promised to go to cinema with my friend in the weekend.

3. 우리는 1년 후에 결혼하기로 했습니다.

We have decided to get married after one year.

4. 내일부터 매일 운동하기로 했어요.

I decided to do exercise every day from tomorrow.

5. 우리는 회사를 시작하기로 했어요. 

We’ve decided to start a company.

6. 휴가 동안 여행을 가기로 했어요. 

We’ve decided to go traveling during our vacation.

7. 수업이 끝난 후에 좋은 친구를 만나기로 했어요. 

I promised to meet a good friend after finishing the lecture.

8. 이번 방학에 부모님과 같이 설악산에 여행을 가기로 했어요.

I decided to go on a trip to Seoraksan Mountain with my parents this vacation.

9. 내일 등산 갈 때 누가 카메라를 가져와요?

- 토니 씨가 가져오기로 했어요.

When we go hiking, who will bring the camera tomorrow?

- Tony has decided to bring one.

10. 새해에 무슨 계획이 있어요?

- 새해에는 더 열심히 공부하기로 했어요.

What plans do you have for the New Year?

- In the New Year, I have decided to study more diligently.

11. 내일 뭐 할까요?

- 등산하기로 해요. (= 등산하기로 합시다.)

What shall we do tomorrow?

- Let’s go hiking.