A stranger at Fellsworth / Sarah E. Ladd.

Enhanced descriptions from Syndetics:

Poachers, mysterious strangers, and murderers converge at Fellsworth Academy, forcing one young woman to a test of fortitude and bravery to stop the shadow of the past from ruining her hopes for the future in this sweet Regency Romance.

In the fallout of her deceased father's financial ruin, Annabelle's prospects are looking bleak. Her fiancé has called off their betrothal, and now she remains at the mercy of her controlling and often cruel brother. Annabelle soon faces the fact that her only hope for a better life is to do the unthinkable and run away to Fellsworth, where her estranged uncle serves as the school's superintendent. Upon arrival, Annabelle learns that she must shed her life of high society and work for her wages for the first time.

Owen Locke is unswerving in his commitments. As a widower and father, he is fiercely protective of his only daughter. As an industrious gamekeeper, he is intent on keeping poachers at bay even though his ambition has always been to purchase land he can call his own. When a chance encounter introduces him to Annabelle Thorley, his steady life is shaken. For the first time since his wife's death, Owen begins to consider a second chance at love.

As Owen and Annabelle grow closer, ominous forces threaten the peace they thought they'd found.