Free man or song
A modern American blend likely combining the prefix Shar- with the name Charmaine or a variant of Charlene. It draws etymological roots from the Germanic 'Karl', meaning 'free man', or the French 'charme', meaning 'song'.
Less common today
Sharmayne isn't in the latest US Top 1000. It last peaked at #5,469 in 1991.
US births per 5-year period, 1990βpresent (SSA data).