Irish has so many ways to say this.

Look here and you can see what I mean:

https://www.teanglann.ie/en/fgb/darling

Maybe if you would post a specific context on when you would use it, we could give you something good.

Thank you so much for a wonderful resource, Tiomluasocein! I'm looking for something along the lines of "Are you unwell, darling?" (between two friends) or "Sleep now, darling." (between a mother and a daughter).

THANKS AGAIN!

A leanbh - is the commonest term in Conamara. It means baby or child. But it's used as a term of endearment. Adults can say it to other (usually younger) adults too but it's never a romantic term. Similar to the Southern United States usage, especially among black people, when they call somebody "child".

It's pronounced Alannah, and that is where that given name comes from.

Thank you Bríd Mhór! I love "a leanbh," but it's getting overused in my novel Looking for another endearment to mix it up a bit!