Mary Balogh's "The Obedient Bride"
A beautifully-written character-driven story about a mismatched couple who make a marriage of convenience, starting out with completely wrong assumptions about themselves and each other, and how they come to accept each other, know themselves, and fall in love. Both of the main characters are actually rather annoying in the first part of the book - the heroine for her insecurity and immaturity and the hero for his conceitedness, but they both change for very much the better as the book progresses.
Much better on the second reading than the first (for me).
