A Matter of Honour / The Chivalrous Rake (Regency Lords & Ladies #18)

A Matter of Honour by Anne Herries
Lord Vincent Carlton requests that his mother invite Miss Cassandra Thornton for a visit. Having recently become an heiress, Cassie knows she needs help to bring her into style, but at least she can now afford to be selective about the man she'll marry.

Unbeknownst to her, however, her late brother had made five of his friends promise that, should he die, one would marry Cassie - and Lord Vincent had drawn the short straw...

The Chivalrous Rake by Elizabeth Rolls
With a broken collarbone, Jack Hamilton was in no mood to have relatives arrive on his doorstep. But the Reverend Dr. Bramley and his daughter were practically penniless, so he couldn't just turn them away. They had obviously left their previous home under a cloud, with Cressida's reputation in tatters.

And then Jack learnt the true reason for their plight, and his chivalrous nature took over. Cressida was in need of a husband...but was he in need of a wife?