I am not sure to exactly which saint you are speaking of but was able to find the following:Saint Mary Magdalene: Penitents & PerfumersMarie Acarie/Mary of the Incarnation: Against...
saint Marie amandine died at age twenty seven and she was the patron saint of laughing because she actually believed that laughing was a healing aid and could make anyone feel better
Since Marie Rivier is not yet declared a saint, I'd guess she's not a patron saint of anything in particular. However, if/when she is, given her dedication to children and orphans, to teaching, and...