(This is a serious answer)
He will fall or he won't. That is if the person goes down, he'll probably go down more unglamorously than a trained person will and is more likely to be injured, which may be desired/necessary depending on circumstances. And, if he doesn't go down, it may be because you didn't off-balance him in preparation for the technique.
That's why you should never feel bad about working with brand-new students in aikido. They are the best for checking if your technique is good, (because they've got little idea about how to respond beyond just going somewhere) or if your regular practice partners have just gotten used to your technique.