Ronronar means "to purr", like a cat. It's an interesting and somewhat unexpected word to find in a song about love and relationships.
In the lyrics, the singer expresses hope that one day he will "ver a fera ronronar com doçura" (see the beast purr with sweetness). This metaphor suggests taming a wild or difficult lover, transforming their intensity into gentle affection. It's a vivid image that makes the word memorable and intriguing.
This song is a playful, patient kind of love song. The singer's partner makes them suffer and shrugs it off, saying a few tears never hurt anyone, so the singer keeps gently asking when they'll finally be ready to grow into the relationship.
Rather than push, the singer chooses to wait. They believe that in time the "fera" (the beast, the guarded, defensive side of the loved one) will soften and start to purr. The title line, "Dou, não dou" (I give, I don't give), captures that back-and-forth: the tease of almost falling in love, pulling back, and almost falling again.
By the end, the promise pays off. As time passes, the love grows, everything starts to feel like too much in the best way, and the old ache of living through that uncertainty finally fades.