Four-Day Fiancé by Mindy McKinley

Litzy:
Lured into her role as set designer for the reality television show World’s Most Outrageous Proposals, Litzy Miller has seen none of the glitz and glamour she was promised. Sure, she gets to travel the globe, but has zero free time to experience any of their locations.
In Belize to shoot a live show for Valentine’s Day, everything goes belly up when the couple splits four days before they go on air. Desperate to keep the show together, Litzy and Chance—the only friend she has on set—are thrown into the role of the happy couple. Aside from learning how to act on camera and trying to keep their story straight, she finds herself falling even harder for the man she’s been trying not to want.

Chance:
Chance Riker has been attracted to Litzy since the day they met on set. But the sunshine of her friendship has been the only thing keeping him from going crazy on this show and the thought of losing that has made him pump the brakes again and again.
But when he suddenly finds himself in the role of her ‘fiancé’, lines get blurred, and he can’t remember why he never took the chance in the first place. Now all he has to do is convince her they’re story is worth a chance.