안녕하세요! The phrases show how certain the speaker is. I wil give you translations for the example sentences as well. 1) - 라고 짐작하다.(짐작합니다) You are not sure what you know, but you are just assuming. 그곳의 경치가 아름다울것이라 짐작합니다. = I assume the scenery is beautiful. 2) - 라고 생각하다.(생각합니다) You are stating that it is YOUR opinion. 그사실을 아는 사람이 많이 않으리라 생각합니다. =I think few people know that. 3)-라고 믿다 (믿습니다.) You believe what you are stating. You are pretty sure about the fact. 잘지내시리라 믿습니다. = I believe you are doing well. = I am sure you are doing great. I hope this helps! If you have more quetions, message me. =] 예문 4번은 요즘 바쁠거라고 짐작하지만 제 부탁 좀 들어주세요. , TEACHER 쌤<3 = I assume you are busy thesedays but I want you to do me a favour.