Firma translates to "signature", a word that isn't common in romantic songs. This makes its use here especially powerful and memorable.
In "Un Papel", Prince Royce sings about a relationship that is reduced to "un anillo y una firma en un papel" (a ring and a signature on a paper). This imagery evokes the cold, formal finality of a divorce, a poignant end to a love story that began years ago.
In "Un Papel", Dominican-American bachata superstar Prince Royce looks back at a relationship that started with wide-eyed hope and ended up as just legal paperwork. He charts the whole timeline through two specific dates: meeting on "un primero de marzo" ("a first of March") as a young boy chasing lost songs, and reconnecting on "un primero de diciembre" ("a first of December") as a grown man looking for the love of his life. He dreams of taking another shot together, dancing, and turning back the clock, but reality hits hard: "Pero somos dos extraños" ("But we are two strangers").
What makes the track stick is how bluntly he sums up a failed marriage. All the years and shared history boiled down to "un anillo y una firma en un papel" ("a ring and a signature on a paper"). In English, we often say a marriage ended up being "just a piece of paper," and Royce uses that exact image here to show how cold a breakup feels after so much warmth. Then, right at the very end, he drops a hilariously petty parting shot: "No cocinaba tampoco limpiaba" ("She didn't cook, nor did she clean"). It is a sudden, funny jab that cuts right through the heartbreak.