Echo by Fiona Davenport

Brodie “Echo” Fauks never expected to fall in love with a voice. Then he overheard Violet Kimball narrating a steamy scene in an audiobook while he was running surveillance on a conman who’d run afoul of the Hounds of Hellfire MC.
Violet’s creepy neighbor was the road captain’s target. When Echo discovered the guy had an interest in her, he came up with the perfect plan—pretend to be Violet’s boyfriend. At least until she realized their relationship was very real.