The Rake’s Convenient Bride by Madeline Martin

A wallflower who trips through life…
Lady Elizabeth Ashbrook is something of a klutz. Only this time the quiet, bookish young lady has literally fallen directly into the path of none other than the notoriously rakish Earl of Darington.
When an accidental encounter appears rather compromising, Lady Elizabeth does what any sensible young lady would, and declares they are engaged.
Even rakes can act the gentleman when necessary and Lord Darington does so by allowing her lie to stand, thus saving her reputation with the ridiculous claim. After all, they only need to be “betrothed” for a few weeks before calling their engagement off.

And it will be called off. Lord Darington is enticing, smooth-talking, and as sure in his footing as he is in his own confidence. That is to say, he is everything Lady Elizabeth is not and the kind of gentleman that should make any lady guard her heart.
In all possible ways, they are entirely ill-suited for one another…aren’t they?