Somewhere To Belong (Daughters of Amana #1) by Judith Miller

Johanna Ilg has lived her entire life in Main Amana, one of the seven villages inhabited by devout Christians who believe in cooperative living, a simple lifestyle, and faithful service to God. Although she's always longed to see the outside world, Johanna believes her future is rooted in the community. But when she learns a troubling secret, the world she thought she knew is shattered and she is forced to make difficult choices about a new life and the man she left behind.

Berta Schumacher has lived a privileged life in Chicago, and when her parents decide they want a simpler life in Amana, Iowa, she resists. Under the strictures of the Amana villages, Berta's rebellion reaches new heights. Will her heart ever be content among the plain people of Amana?