Wyatt's Wager (Cowboys of Cauldron Valley #6)
Caroline Lee

Because there’s only one woman in the world he can imagine marrying, and as his best friend’s little sister, she’s off-limits.
Artemis Weston has had a crush on her brother’s best friend for as long as she can remember. But Wyatt has made it clear he has no intention of settling down…ever. So she’s thrown herself into her career as a vet tech, and vowed to forget how good a certain green-eyed cowboy could make her feel.
Right up until the phone rings, and Wyatt’s on the other end, asking for a date.
When his best friend offers him a wager, Wyatt jumps at the chance to spend time with Artie, and dating her is just as wonderful as he imagined. But sooner or later, she’s going to figure out he’s only with her because of her brother’s bet, and that’s when their hearts are going to be hurt.
Maybe, for once, it would’ve been better to lose this particular wager…