The Viscount’s Promise by Christina Britton

Lady Emily wants nothing more for her brother Caleb than a happy marriage. Soon to be wed to Miss Imogen Duncan, Lady Emily is overjoyed at the wonderful match. But with a wedding comes the one thing she cannot handle: people, and their stares. Her face left scarred by an accident that killed her twin, Emily would rather be alone forever than suffer the eyes of a crowded room.
Desperate to socialize his painfully timid sister, Caleb asks his dearest friend Lord Morley to shadow her closely as a companion. But his abrupt and surly nature only provoke the worst in her. Little by little, Morley chips away at her shy demeanor to the spitfire of a person within. Emily, taking little of Morley’s crude remarks, finds the kind boy she worshipped years ago.

When their defenses are down, will they be able to resist what they can finally see?