The Unintended Bride (Zebra Ballad) (Once Upon a Wedding)

is part of the Zebra Ballad line.
==Book Description==
The Fensters were like many other proper Victorian families--in every way but one. Ignoring the grim convention that one married for wealth and title, these spirited siblings followed their hearts...and vowed to wed only for love.
THE HEART KNOWS — Although her adoring sister assured her that she needn't marry for title or money, painfully shy Hero Fenster longed for romance. Arthur Watterley, the man she'd lost her heart to years before, ever knew her feelings. Nor would he--even as she agreed to help him search for a rare edition of Le Morte d'Arthur. At least she would enjoy the pleasure of his company. But when they found themselves accidentally locked in a bookseller's shop together, their innocent friendship suddenly became an item for the scandal sheets--and Hero found herself in a wedding gown! A marriage of obligation was hardly the romance she'd yearned for...unless Arthur could convince her that he was the dashing--and passionate--hero of her dreams
(Description from paperbackswap.com)