You’ve Got an Earl by Bianca Blythe

An earl mistakes a debutante for the woman hired to play his faux secret beloved.
Percival, the Earl of Plymouth, is in trouble. Terrible trouble. His aunt is eager for him to marry. Since Percival has no desire to be thrust onto the marriage mart, he may have told her he has a secret beloved. Fortunately, Percival’s best friend Sebastian volunteers to find Percival someone inappropriate with whom to pretend to have an amorous relationship. After all, Percival’s aunt won’t desire a scandalous future countess.

Sabrina Holt has adored Percival ever since she first laid eyes on him. When she wanders into Percival’s library during a ball, and he begins to kiss her, she knows he’s felt the same way as she has for all these years.

Percival is pleasantly surprised at his friend’s pick. The woman in the library’s lips feel perfect, and his aunt is appropriately shocked to discover them. Unfortunately, Sabrina is not the woman his friend hired for him to be caught with. If only Sabrina weren’t the wrong faux beloved, and if only Percival weren’t tempted to give her his heart.