Help! I can't remember the title of this book

I am trying to find the name of a historical romance novel. The story is about two sisters who live in poverty in the country. Their father, the vicar, just passed away and the girls need to move out of the home they grew up in to make room for the new vicar. The elder sister wants to find a suitable husband for her extremely beautiful but naive and sweet sister Celia (or Cecilia, I'm not sure of the spelling)(she is described as looking delicate and fragile with hair a silvery pale blonde color) Someone that has money and can take care of her. Cecilia is already in love with the new vicar, but her sister does not feel he is worthy of her and that she is wasting her beauty in the country. The elder sister hopes that one day she may live her dream of becoming a teacher once her sister is settled. Until then, she refuses to pursue her dream. The elder sister writes to her mother's best friend and her godmother, Lady Norwood(I think that's her name) to ask her to chaperone and introduce them to eligible bachelors in London. Lady Norwood doesn't write back, pretty much ignoring them, until the elder sister sends a new letter mentioning finding a locket that might have possibly belonged to Lady Norwood. Lady Norwood's nephew or stepson, Sir Richard Norwood, I think that's his name, arrives to escort the girls to the Lady Norwood's London home. Sir Richard automatically takes a protective attitude towards the Cecilia and is judgmental of the older sister because he feels she thinks only of herself and is trying to push Cecilia into a world where she will not feel comfortable. Together with the sisters and Celia's bird Nipper, they travel to London and then Bath so that lady Norwood can take the waters. They meet many men, including Lady Norwood's son. The gentlemen are so captivated by Cecilia's ethereal beauty, naturally they try to court her but she is very shy and timid. So, the older sister shined enough for both of them. They were an instant success. Lady Norwood is not only rich, she is also very vain and feels resentful and jealous of the attention her guests receive. But Lady Norwood wants to get her hands on the locket because it reveals the truth that she is not actually the real Lady Norwood but was instead a maid to the real Lady Norwood, the mother of Cecilia and her sister. There mother and the maid switched places with each other so she could marry the poor man she loved. Her maid impersonated her and married nobility. Everything was fine until finances started declining for their family. The girls' mother pleads for help from the fake Lady Norwood by asking for her to send some of the jewels that belonged to her when she was a noble woman. But, the selfish woman refused to give away anything to help her childhood friend. When their mother said she would expose her because she desperately needed money for her children. The imposter Lady Norwood agreed to meet her at a hotel. There she poisons her "friend's" tea, killing her and keeping the secret for many years. To get the locket, and also to keep the murderous secret, Lady Norwood introduces the girls to society. The girls meet with several mishaps and attempts on their lives. Through it all Sir Richard and the older sister fall in love with each other. Despite his misunderstanding of her motives for trying to find a husband for her sister. Eventually, the truth is revealed and in an attempt to get rid of the girls once and for all, Lady Norwood sets fire to their bedroom and locks the girls inside. Unexpectedly, Lady Norwood's son turns on her. He takes the jewel chest she's holding and pushes her into the burning room with the sisters and their bird. Sir Richard Norwood and a few other men that had taken a fancy to either Cecilia or the elder sister, came to the girls' rescue, but Lady Norwood runs after her son, who attempted to go abroad with the stolen jewels. Sir Richard intercepts him and to prevent a scandal, he takes the jewels, gives him a little money, and puts him on a ship, telling him never to return or he will have him put in prison or hanged, scandal be damned. In the end Cecilia chooses to marry the County vicar, whom she loves and who also came to Lady Norwood's house to ask for Cecilia's hand in marriage. Sir Richard gives consent and the older sister finally gives her blessing. Sir Richard then proposes to the elder sister. They marry and live happily ever after.
That's pretty much the gist of the whole book. I think it's a regency historical romance. If anyone knows the name of this novel, please share it with me. Thanks in advance.

Its "A Dangerous Affair" by Mona K. Gedney.