"Θα έχω πει την αλήθεια."

[jaye16]

"I shall have told the truth." is an accepted translation and should have been accepted. If it wasn't it might be due to a technical problem please report that directly here:

https://support.duolingo.com/hc/en-us/requests/new

[Glossmad]

I was marked wrong for 'I will have spoken the truth'. Pretty much the same thing.

[Dimitra956826]

I just added this one, thank you ^.^

[Nicole966706]

Why « I will have told the truth» instead of « I shall have told the truth»?

[Nicole966706]

I shall have told / I will have told?

[Walt1965]

I shall have told is correct future perfect. I will have told implies determination.