Grace Livingston Hill 
The Obsession of Victoria Gracen 

The straitlaced, conservative little town of Roslyn was shocked when Victoria Gracen opened her home to young Dick Gracen. Oh, they understood that he had just lost his mother and he needed a home… but everyone knew that Dick was a hopeless case—a reckless troublemaker who they were sure would bring gentle, lovely Victoria nothing but grief.
Victoria ignored their dire predictions. Instead, she set about to tame the boy’s wild ways with tenderness and faith. Everyone knew she would fail… but they hadn’t counted on one thing: It would take a heart of stone to resist Victoria Gracen!