Movie name is something like Hailsham - set in England

Bound by duty and shadowed by violence, a young heir and his bodyguard find love—knowing danger may steal their chance at a future together.

As children, Kathy, Ruth, and Tommy spend their childhood at an idyllic and secluded English boarding school. As they grow into adults, they must come to terms with the complexity and strength of their love for one another while also preparing for the haunting reality awaiting them.