Amanhece means 'dawns' or 'breaks' when referring to the day. It's a beautiful and evocative verb that paints a picture of a new day beginning.
In the song, Gusttavo Lima uses it to describe the painful routine of waking up without his loved one: "Quando o dia amanhece eu sinto que você ainda está nessa cama" (When the day dawns, I feel that you are still in this bed). This word captures the bittersweet feeling of a new day bringing fresh sorrow, making it a poignant choice.
"Mil Vezes Cantarei" is a song about holding onto a love that's already gone. Every morning the singer wakes up and still feels his ex-partner beside him, and the ache of missing her brings him to tears.
He clings to one hopeful idea: if he keeps singing this song, over and over, it will somehow reach her heart no matter where she's gone, and maybe convince her to come back. The title itself means "I'll sing a thousand times" - a promise to keep singing until the love that once felt so certain finds its way home again.