This song was written by Anne Lister, though I believe she spells the title Rosemarie, with the accent on the last syllable. It's a medieval-style tale about a maiden who is deserted by her faithless lover - but with a twist at the end.
I don't know how Anne would feel about her work being posted in a public forum, but if you PM me with an email address I'll forward it to her and let her decide what she wants to do. I really can't act without her permission, so this is the best I can do. It's really is a lovely song -