It's from Scott's 'The Heart of Midlothian', 1818, where no tune is specified. Scott himself could not note tunes, but this is Scott's revised and condensed song and doesn't qualify as a version of a Child ballad (like his Jock of Hazeldeen). There are 13 tunes for various versions of Child #65 in Bronson's 'The Traditional Tunes of the Child Ballads'.