What is the name of this book?

There is a girl, she thinks that I have a crush on her, but I
don't. I am trying to avoid her. One day she told me about some book, and I promised to read it, but forgot the name and the author. And I can't ask her, because she'll think that I am after her. It's about a guy called Mervyn Keene. He was young, rich and handsome, an officer in the Guards. But there was a tragedy in his life. He loved Cynthia Grey, the most beautiful girl in London, but she was engaged to Sir Hector
Mauleverer, the explorer. He went around, outwardly cheerful, in a ceaseless pain inwardly. Her wild brother Lionel committed a crime, and asked Mervyn to accept the blame. He did, for Cynthia's sake. He went to prison and after release moved to the South sea islands and became a beachcomber. Then Cynthia and her husband arrived to the island, and he broke into their place to take a rose from her room, he met Cynthia, she recognised him, and he told her that her brother was guilty.

Then her husband came in, took him for the burglar and shot him. They asked Cynthia what was missing, and she said: "Only a rose".

Bertie, it's called Mervyn Keene, Clubman. As for Madeline, I'm sure Jeeves will set things right between her and Gussie, and you'll be off the hook..

King Arthur & His Knights

Lancelot is dead!!

Is this book by Rosie M. Banks??

Madeline Bassett is such a bore! One more word about "Mervyn Keene, Clubman" by Rosie Banks and Bertie will lose his will to live.