The repeated part of the lyrics is the best part of this song, "Rasa kehilangan hanya akan ada jika kau pernah merasa memilikinya." It means, "The feeling of loss will only exist if you've ever felt having."
Do you have more proper translation?
"A soft summer rain, a smile that hides a pain
Why should you be ashamed?
'Cause in every life, a little rain must fall."
Truth, Cry, and Lie - Letto