애쓰다 and 아/어보다 The two are actually quite different. - 애쓰다: work hard, exert oneself in earnest to an end. (애 is an old word for guts, so it's "even using your guts") - ~아/어 보다: try and do something; try tentatively; try something and see what happens. (light and casual) 보다 (see) is used here as a helper verb to add the sense of "try and see what happens". So the two phrases share the meaning of "trying" but are also very different as far as the seriousness goes. * "Back then,your father was only trying to protect you so stop blaming him!" => 그때는 (네) 아버지가 널 보호하려 했던 거니까 아버지 원망은 그만해 (word for word) => 그땐 (네) 아버지가 널 보호하려는 마음에서 그랬던 거니까 고깝게 생각 마. (more natural) * "Think about how i must have felt fifteen years ago!" "십오 년이 전에 어떤 느낌인지 좀 생각해봐!" * "15 years ago" => 십오 년 전에. 이 is never needed. * 느낌인지 (present tense) => 느낌이었는지 (past) or 느낌이었을지 (past - more vivid). * 느낌이었을지 is more emphatic than 느낌이었는지 which is more factual. "내가 십오 년이 전에 어떻게 느낀걸 좀 생각해봐" * 어떻게 느낀 걸 => 어떻게 느꼈는지 / 어떻게 느꼈을지 or 어떤 느낌이었는지 / 어떤 느낌이었을지. => 십오 년 전에 내가 어떤 마음[기분, 느낌]이었을지 생각해 봐. => 십오 년 전에 내 마음이 어땠을지 생각해 봐. Your translations are close, but 느낌 has a slightly different nuance. If one feels something compelling about a serious matter, 마음 is usually the better choice. 느낌 is used more for reactions and perceptions to something external, usually more subtle and not as important.. Examples: - 나는 그를 돕고 싶은 마음이 간절했다: I felt a sharp urge to help him in my heart. - 나는 그가 간절히 도움을 원한다는 느낌을 받았다: I felt that he was desperately seeking help. Feel free to ask if you have further questions.