Well I just had to reply to this thread, with the obvious name change!
I am Rosamund, and I have never liked it! I agree with people who say the mund bit is ugly sounding. My poor Mum, who obviously loves it, has never understood my dislike of it, but to me I have always hated it. I go by Ros, or Rossie to my family, and that's fine, but I always dislike being somewhere like the doctors, dentist etc where they call you by your full name.
I've just turned 50 and my opinion isn't going to change if it hasn't by now! Don't do it OP, choose something easier on the ear!