Re: settled then?
"It's settled then" -- We have reached an agreement/decision. (Or, others have reached an agreement/made a decision and we will abide by it.)
It could be deciding where you'll go for lunch or what movie to see. It could be as important as calling off a wedding or getting divorced.
It's settled, then. We'll meet at 7:50 outside the theather and we'll watch the 8:00 show of Harry Potter.
It's settled, then. I'll see if I can live with my brother for a while, and I'll start moving my stuff out tomorrow.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.