This will only get responses from the wrong type of woman. So you are writing to many women. Do not send out a standard letter. Read their bio information carefully and ask them questions relating to this information. Ask about her family and where she lives.
Some women get letters and find it hard to start a reply.
This way the women can start writing to you by replying to some of the questions you asked. Above all show some interest in them. Make them feel special. Mention that you liked her picture. I cannot stress the importance of sending a photo.