The Belden text from 1906 at the head of the list in the Traditional Ballad Index was taken from the Civil War diary of E. J. Sims, "sent to me in 1906..."
Belden's text is incomplete, as shown.

BANISHMENT

My dearest dear, the time draws near
When you and I must part,
But little do you know of the grief and the woe
Of my poor troubled heart heart heart heart.

Or what I suffer for your sake,
You who I hold so dear,
-------
-------

I've one request to make of you,
If I may be so bold:
To place a room within your heart
My secrets for to hold

-------
-------
That this vain world may never know
How deep I am in love with you.

I wish my heart was made of glass,
That in it you might behold
Your name in secret there lies wrote
In letters bright as gold.

-----
-----
If I prove false to you, my love
The raging sea will burn.

If I prove false to you, my love,
-----
The crow that is so black
Will surely turn to white.

Oh, do you see your turtle dove
A-sitting on yonder barn,
A-mourning for its own true love
A I do mourn for mine?

Sounds like a folk version of a composed 19th c. piece. The last verse could be an addition from another song.

Belden, H. M., editor, 1940 (1973). Ballads and Songs, Univ. Missouri Studies, vol. XV, no. 1.