In 1895, she accepted her brother’s call, Father José Marchett, to follow him on his mission to Brazil to take care of Italian immigrant orphans. With her mother and two young girls, she was introduced to John Baptist Scalabrini and so constituted the "Abandoned and Orphans Servers" on October 25, 1895.

To Mother Assunta, Jesus was presented on the impoverished, orphans, sick and migrants. She felt happy and "honored to have been called to the apostolate" and to serve charity to the neediest. She dedicated her youth as being a mother to those who had lost their own to the orphanage. She dedicated her heart end her terrene days to the little orphans.

The Missionary Scalabrinian Sisters have Mother Assunta as a model of brave and tireless missionary dedication on service to charity.
During an attendance to a sick person, her leg was injured that brought her many years of suffering and pain. She died in St. Paul Orphanage, Brazil, on July 1, 1948.
The diocesan process for the Beatification of Mother Assunta Marchetti was concluded on October 25 1991 in São Paulo, Brazil. The process was sent to the Congregation for the Causes of Saints in Rome where it is being prosecuted. There are innumerous graces intermediated by her.