Eternal Vows - a time travel romace and fantasy adventure by Chrissy Peebles.

Amazon link: http://www.amazon.com/Eternal-Vows-First-Series-ebook/dp/B007HPDFBC

BOOK TRAILER: http://www.youtube.com/watch?v=n_w-eZwPJbA

Never marry a stranger...even if he is a drop-dead gorgeous immortal king.

Never pretend to be a princess.

And most importantly...never slip on an ancient wedding ring you know
nothing about.

Sarah Larker returns to a cave where her sister disappeared ten years
earlier. She walks through a portal and is mistaken for a runaway
princess on the run by a dangerous immortal king in medieval times.
Her plan is bold as well as daring—become this princess, wed the king,
and slip on an ancient wedding ring that will unlock the portal back
home. Then find her sister and run as fast as she can out of Dodge.
But taking on the identity of Princess Gloria comes along with
dangerous consequences; and slipping on the ruby ring comes with an
even higher price.
***
I have an interesting tidbit to share that most people don't know
about Eternal Vows. It was a NaNoWriMo writing project. Most people
think November is just another month in the calendar year, but for
writers it's one of the biggest writing challenges ever. The event is
called NaNoWriMo and it happens every November! The challenge is to
complete an entire novel in just 30 days. It's not about quality, but
quantity. The word-count goal is 50,000 words. Writers can use a
website to track their own progress, create profiles, upload excerpts
of their novels, and participate in discussions in different forums.

I embarked on my great novel-writing adventure with much enthusiasm,
spending the month of November pounding away on the keys any free
chance I had. I actually wrote 50,000 words! Of course, I spent the
next few months editing and whipping it into better shape. Last year,
more than 36,000 writers reached the 50,000-word goal.

I loved Sarah's story and had so much fun with her feisty character.
This was one of my favorite stories to write. And I can't believe I
did it in a month! (not the editing and fine-tuning, of course)