Brazilian fashion model Trentini was born in Panambi, Rio Grande do Sul, Brazil. Trentini is the youngest daughter of Lourdes and the late Jacó Trentini, who died when she was one year old. Her older sisters are Franciele and Élen. Although she had never worked before, Lourdes got a job as a public employee when Jacó died and raised her daughters single-handedly.
In 2000, Trentini was discovered walking down a street in her hometown by an agent, the same one who scouted Gisele Bündchen, and soon afterward she moved to São Paulo, a common destination for young Brazilian models. She was frightened to be alone in the big city, as Panambi had only 40,000 residents.However, her modeling career immediately took off, and after a year, Trentini moved again, this time to New York City. She couldn’t speak English but quickly learned. Trentini’s breakthrough came when designer Marc Jacobs cast her in his Marc by Marc Jacobs ad campaign, photographed by Juergen Teller.
Trentini dated photographer Victor Demarchelier, son of legendary French photographer Patrick Demarchelier for about three years. Immediately after breaking up with Demarchelier, in early 2010, she got back together with Brazilian photographer Fabio Bartelt, who was her first boyfriend. In October 29, 2011, both Trentini and Bartelt announced they were engaged. In March 3, 2012, Bartelt and Trentini were married on a church in Itajaí, Santa Catarina, Brazil. On 23 February 2013, the couple announced on Twitter that they were expecting a baby.