An Uncertain Heart — June Tate

Belgium, 1917. At a military hospital in Poperinge, close to the horrors of the front line, Sister Helen Chalmers strives tirelessly to save the many injured soldiers brought in from battle. The hardships of war and the need for comfort throws Helen into the arms of the eminent surgeon Captain Richard Carson - although she knows a romance with a married man will never last.
It's not long before Helen is swept off her feet by Captain James Havers, a man with whom she can see a future. When James is injured in the fighting, he is sent back to Britain to recover. But it's soon clear his injuries are more than just physical; the violence of warfare has left him a changed man. Helen must summon what strength she can to help the man she loves overcome the lasting and devastating effects of war.