Why does Senhor Pimentel send Graça to the Petrópolis Sion School in the novel, The Air You Breathe?

Senhor Pimentel orders that Graça be sent to the Petrópolis Sion School run by nuns 2,000 kilometers south of Riacho Doce after her apparent attempted suicide. He is angry that she sabotages her relationship with the suitor he presents for her and wants the nuns to give her stability and reform.