Wow what a twist

For a romantic comedy that airs during Christmas time, this was easily the best one I've watched in a long time.
Totally wasn't expecting that twist and to be honest the ending was a little bittersweet for me.
Spoilers for the ending:
I thought it was bittersweet because they had no idea the little girl was their dead baby. Imagine if they knew how different everything would be. All the last time the mom was spending at work, all the fighting and arguing when their freaking miscarried baby is grown and standing in front of them