I'm pretty sure you can forces it through your video card's control panel... might be too resource-heavy to do so though. I love AA and force it usually when no in-game option is provided, but I know these open-world RPGs can make forcing AA on them too much for a single GPU to bear.
I don't think I forced AA on Divinity 2 though... pretty sure the jaggies weren't too bad for me. I forced AA on Risen though, that game was a jaggie mess without it.
