A Dangerous Heart by Lacy Williams

Former U.S. Marshal Isaac McGraw wants nothing more than to forget his past and live in isolation on the family ranch. But his meddling family has cooked up other plans—plans that include matching Isaac with a mail-order bride who has two young boys in tow.
There’s something about Clare Ferguson that bothers Isaac…more than the haunted look in her eyes and the way she’s constantly glancing over her shoulder. Against his will—and better judgment—he finds himself drawn to Clare and her cheery disposition.
When Clare’s secret past and relationship to an infamous outlaw is revealed, Isaac must break free from the chains of his past to keep his new family safe…