make it known
When you are old, you wont care if your love wasnt returend- only that you made it known how you felt.
it means- 네가 나이가 들면, 네 사랑이 되돌아 오지 않아도 너는 신경쓰지 않을거야.
But i dont understand- 'only that you made it known how you felt.' It means -' 오직 네가 알게될 것은 네가 어떻게 느끼는지야.' 즉, 너는 그/그녀를 얼마나 사랑하는지를 느끼게 된다는 뜻인가요??

Question

make it known
When you are old, you wont care if your love wasnt returend- only that you made it known how you felt.
it means- 네가 나이가 들면, 네 사랑이 되돌아 오지 않아도 너는 신경쓰지 않을거야.
But i dont understand- 'only that you made it known how you felt.' It means -' 오직 네가 알게될 것은 네가 어떻게 느끼는지야.' 즉, 너는 그/그녀를 얼마나 사랑하는지를 느끼게 된다는  뜻인가요??

Answer

-> I am using Google translate
Love here is an emotion.
The writer is not talking about a lover
-> That translates to
여기에 사랑은 감정이다.
작가는 애인에 대해 얘기하지 않습니다

I believe that the writer is saying that you will remember either the return of love or the rejection of love, rather than the emotion itself.