If The Boot Fits by Karen Witemeyer

Determined to prove that cattle king Eli Dearing has no justification for evicting his stepmother and half brothers, Asher Ellis uses the cover of a fancy ball to break into the Three Cedars ranch house to search for proof of wrongdoing. On the verge of discovery, he flees, but a boy's cry compels him to make a daring rescue.
Spunky and independent, Samantha Dearing balks when she learns the ball her father is hosting in her honor is nothing more than a matrimonial ambush. Taking a break from her unwanted suitors, Samantha spots a thief fleeing her home. When the stranger ends up saving her brother's life, she hides the only clue to his identity left behind--his boot--and resolves to find him herself.
But when Samantha encounters the older brother of a student she tutors, all thoughts of the bootless mystery man vanish. And although Asher tries to keep his distance from Samantha for reasons of his own, a series of suspicious accidents befall her, and his protective instincts flare, no matter the cost to their future.