Tender Is the Storm by Johanna Lindsey

Headstrong heiress Sharisse Hammond wants no part of the New York society marriage that has been arranged for her. So she heads west across a vast and dangerous land -- with no intention of honoring her agreement to become the mail-order bride of a rugged Arizona rancher.

But Lucas Holt needs a wife -- any wife -- if his plan to destroy his most hated enemy is to succeed. And this gullible Eastern lady would do quite nicely. However, their separate schemes to use one another are complicated by raw, aching passion. For Lucas's beautiful, unsuspecting pawn was not supposed to be so irresistible alluring. And freedom-loving Sharisse never dreamed she could ever desire one man so much!