Sara responded almost immediately. The song is called "Parting Hand" and the corrected lyrics are as follows.

I'm still uncertain about verse 4, because her email was a bit vague, and I didn't like to push my luck by badgering her again. Note that, at the end of verse 1, although she writes "Before we part", she definitely sings "Before we start" in the recording of her I made in a singaround at, I think, Beverley FF, in the late 80s / early 90s.

Parting Hand (sung by Sara Grey)

1
I'll give to you my parting hand,
To wish you well in a foreign land;
All the secrets of my heart
I want you to know, before we part/start.
(repeat last line)

2
My dearest dear, I love you well;
I love you more than tongue can tell;
All my friends, and relations too,
I'd leave them all for to go with you.

3
Grass is green, and the rose is red,
You are my love 'til I am dead;
When I'm gone and laid to rest
Remember the one who loves you best.

4
Some will have clothes, and some have stones,
some will weep, and some will mourn,
Some will lie, for the lovers cry,
But in our graves we all must lie.

5
Some will weep in a sorrowing way,
For the loss of one who cannot stay,
And if he's gone he can but go,
That's what makes me love him so.

6
Just one thing, that I've been told,
My love is like a ring of gold -
Round and pure and has no end,
My love is like a trusted friend.