If the show keeps Bashere (which who knows) I think the FUNNIEST and most in character way for him to address Deira being a Dark Friend is him being very nonchalant about it.

Bashere: Ah yes, my dear wife passed away a few years ago now. Tragic. I miss her every day.

Rand: I'm so sorry. What happened?

Bashere: Oh she tried to kill me in my sleep.

Rand: What.

Bashere: Didn't realize she was serious at first. Usually when she came at me with a knife in the bedroom it was for purely recreational purposes. Turns out she had decided to go over to the Shadow without telling me. dreamy sigh She probably would have got me if her knife hadn't caught on my ribs.

Rand: W h a t.

Bashere: After I disarmed her she confessed everything- all she demanded in exchange was the chance to plan her own execution. Classy woman right up to the end. Told me that if she didn't do it herself I would make the whole thing tasteless and gauche. Probably was right. She put together a beautiful ceremony: scattered king pennies, a silver chased ax, white silk for all the attendants to make the bloodstains really pop. It was a real crowd pleaser.

Rand: W H A T.