"She has a boyfriend."
Translation:Tá buachaill aici.
That's a literal translation of it, and reeks of Béarlachas. Very often it's just buachaill for 'boy' and 'boyfriend', same as how fear can be used for 'man' and 'husband' (though chéile can be added to formalize the distinction)
"Buachaill chara" is the standard Irish for boyfriend, as I learned in school. It should be accepted here. However "buachaill" on its own is fine as well.