Sacrifice (Abram's Daughters #3) by Beverly Lewis

In The Sacrifice, Leah Ebersol has no choice but to believe the worst: Her older sister, Sadie--and Leah's own beloved Jonas--have betrayed her. Now, two years later, Leah still misses them both, though loyal neighbor Gid continues to bide his time. But when tragedy befalls the Ebersols, Leah must make a difficult choice.