..I totally get that look on Frodo's face.
I always try to give me kids an encouraging word, hug or smile before they have to confront something they know is going to be hard -- and I can tell you that not once have they ever smiled back at me! Mostly, I just get an eye roll or a "look that says, ok, sure, I know I have to do this, but are you sure you can't just do (fill in the blank) for me?" and then they sort of frown at you when you don't do anything but continue to smile at them instead...
I used to think I was just inept at what to do to really help my kids, but now I realize that it really helps for Moms to do something a bit aggravating at times like this, as then kids start thinking about how moms say the stupidest things and forget their nervousness. I think even kids recognize this, because afterwards, when the tough thing is done and everything is fine, that's when I get the smile or the hug returned...
(Sorry for going all "mom" on you here, but I just dropped a kid off at college so I just got that look yesterday, so it's sort of fresh in my mind!)