Examples for rare 1-handed weapons are:
1.7% chance to Stun on hit
2.1% chance to Freeze on hit
1.4% chance to Fear on hit
Rare 2-handed weapons can get as much as 5% for these sort of affixes but those numbers are still too low to be of any use.
The only weapons with adequate proc rates are legendaries such as Echoing Fury with up to a 22% chance to fear on hit.