Recomeçar means "to restart" or "to begin again." It's a hopeful and active verb that captures the essence of trying to rekindle something that has faded.
In the context of the song, the singer, despite his partner forgetting their anniversary, expresses a strong desire for their love to recomeçar (restart). It signifies a longing for renewal and a fresh start in their relationship, making it a poignant and central theme of the lyrics.
Gusttavo Lima turns an anniversary toast into an aching plea. He opens with the loss already settled — "Sei que acabou, aquele seu amor" ("I know it's over, that love of yours") — before the title line arrives as something between a celebration and a confession: "Parabéns pra você, parabéns pra nós dois" ("Congratulations to you, congratulations to both of us"). Even as she forgets, his love keeps growing — "Continua em mim crescendo, esse seu jeito louco de te amar" ("It keeps growing in me, this crazy way of loving you"). By the final chorus he's down to one request, repeated like a wish: "Eu te quero do meu lado, pra ver o nosso amor recomeçar" ("I want you by my side, to see our love begin again").