The translation of the song is not clear enough to make a perfect interpretation. However, from what I can gather from the sporatic wording that did translate over, the author of the song is writing about an inability to know and express love. And how this causes great pain for him. He is only able to show the capacity of love that God gave to him.

He also writes about how this inability to express love is part of Bossa Nova, and that there are others like him, other "untuned ones." The heart beats in the chest of the untuned ones, those who do not speak out do have an opinion.