One Knight in the Forest by Catherine Kean

When Lady Magdalen Suffield finds a letter ordering her best friend’s husband to commit murder, she flees into the woods. Pursued and injured, she collapses into the strong arms of Lord Cynric Woodrow, the local sheriff.
As Cyn treats her wound in his forest home, he wonders why she’s running from a man he considers an honorable friend. She refuses to confide in Cyn, but as his fascination with her grows, he must choose between loyalty to her or to his friend. Can Magdalen win his trust and stop the murder, or will the danger destroy far more than the love Cyn and Magdalen seem destined to share?