It wouldn't hurt a bit to split test your page on this.
Yes, I agree that risk reversal is important ... it's what all the 'gurus' teach. However, this has become envogue more and more over the years.
Everybody is feeling the pressure to give the guarantees because 'the other guy is doing it'.
Don't get me wrong, I think providing a guarantee is very smart. However, just test it. That'll be your final answer.
If you're offer and product and sales page (with video) is that good, people will overlook the guarantee, a lot. Especially if it's priced right.
I've been in the lead business and providing lead generation services for over 7yrs now with NO guarantee. It just doesn't work for my business, but it certainly hasn't hurt mine. Though it is very different that info product business or software selling.
Hope this offers another viewpoint worthy of consideration,
Mark
P.S. CharlesKirkland has some good info and I would default to his expertise.