Three Ways to Catch a Cowgirl by Linda Goodnight

Step One: Unlock her frozen heart.
She can’t risk her heart again.
Mesa Brazos had her chance at happily-ever-after and she lost everything. After her marriage imploded, the trick-riding cowgirl had a crisis of faith that sent her home to Refuge, Texas. Now she’s holed up on the ranch she and her sisters inherited, training horses. She’s not interested in falling in love again. It’s too painful.
He has a deep need to protect.
Undersheriff Evan Young is a single dad and his daughter—a heart transplant recipient—is everything to him. So what if he’s a little overprotective? After losing his wife, he couldn’t bear it if anything happened to his little girl Ava.
When Evan’s protectiveness stifles Ava, it’s Mesa who brings back the spark of joy to his little girl’s life. But will the secret of Ava’s transplant break Mesa’s heart all over again?