V-기로 했다
This pattern means 'to decide to do something.' Attach -기로 했다 to a verb stem when you want to say you made a plan or decision. It is very reusable in everyday Korean. Example: "저는 매주 숲에 가기로 했어요." = "I decided to go to the forest every week." In the story, this appears in "데려가기로 했다".
저는 매주 숲에 가기로 했어요.
I decided to go to the forest every week.
