I don't know this song, but it's published in Nóirín Ní Riain. "Stór Amhrán". Cork: Mercier Press
Lyrics and translation below are copied from "Stór Amhrán"

Éamann Mhagáine

Idir Chaiseal agus Dúrlas do dhearcas mo rúnach
Go hatuirseach tabhartha am' choinnibh sa ród
Do labhair sí go tláith liom, de chómhrá bhinn mhánla,
Agus do chuir sí romham fáilte agus céad míle póg.

"Seo litir óm' mháithrín
Á dtabhairt anseo id' láthair, a óganaigh óig,
Go bhfaigheá-sa na táinte le spré 's stoc le n-áireamh
'Gus mise mar bharr air sin choíche 's go deo."

"Agus inis-se dod' athair is gan dearmad dod' mháithrín,
Go bhfaigheá-sa mé le pósadh, a chailín bhig óig,
Ach go bhfuilimse in áirithe le bliain is í raithe
Ag iníon Sheáin Dáibhis ó Chontae Mhuigheo.

Is ná bíodh sé le hinsint anois ort ná choíche,
Fill abhaile chun do mhuintir' a chailín bhig óig;
'Mise Éamann Mhagáine nár las riamh le náire,
Is gheobhair i Sliabh Bán mé nó san áit is mó ceol"

Between Cashel and Thurles I saw my loved one,
wearily, worn out, coming towards me on the road.
Wanly she spoke to me with sweet gentle words
and she put a welcome before me and a hundred thousand kisses.

"I have a letter here from my father and my little mother
to bring to your presence, O young man -
(saying) that you would get herds of cattle and sheep
and myself on top of that for ever and ever."

"Tell your father and, without any mistake, your mother
that you would get me as a husband, O small young girl;
except that I have been engaged for a year and nine months
to the daughter of Seán Davis from County Mayo."

"And let it not be an embarassment to you now or ever,
return to your people, O small young girl;
I am Éamann Mhagáine who has never been put to shame
and you will find me in Sliabh Bán or in the best place for music."