To keep or not to keep

I was going through some of my older family portraits on the hdd and I am trying to print out some to create a physical portfolio - this one has me a little stumped and I'm erring on the side of it's NOT a keeper. This is brother and sister and whilst the parents loved it etc etc I'm not really 100% sure if it will enhance my sale-ability. Critique welcomed and reasons why you think it may NOT be a keeper. This was her 'usual' smile, and yep, it does look a little forced, agreed.

