Help romancing Isabela in Dragon Age 2 ?

I'm trying to get the achievement for the romance subplot but I'm lost. I'm in act three, I have full friendship with Isabela but during act two I didn't sleep with her at the manor. I'm just about to embark on her mission to kill a pirate or something. Is it still possible to romance her?|||I think you are still able to get the romance scene. You will only know when your about to end the game. Right before the final fight, you get a chance to talk to everyone who is still with you. Make sure you make a promise with her, and after that it should unlock.|||As long as you didn't click the broken heart option when talking to her or sleep with anyone else your romance should still be active. You don't get the achievement until the very end of the game.