Breaking Promises by Elle James

Delta Force Operative Asher Gray otherwise known as “Smoke” is on temporary assignment to the US Embassy in Jerusalem. Never one to get involved too deeply with the opposite sex, he finds he can’t keep his eyes or hands off the ambassador’s niece who happens to be the man’s bodyguard.
Danica “Danny” Turner learned her fighting skills in the Army and then in the MMA arena. When she’d had enough of beating her opponent’s heads in, her family convinced her to be her uncle, the US ambassador to Israel’s bodyguard, only to find a Delta playing double duty to her assignment. Though she’s hot about having a backup, she can’t help falling for the annoying man.
When all hell breaks loose at a formal function, Danny is taken hostage. Smoke and his team of Deltas must find Danny and rescue her before her captor kills her. Smoke will stop at nothing to save Danny and to confess how he feels about her.