|This spell forms a mystical bond between the caster and a wielded short blade, making the blade much easier to use.|
Sure Blade is a level 2 Hexes/Charms spell which temporarily adds +5 to +15 accuracy to all attacks with your currently wielded short blade. It has no impact on any other weapon type. The size of this accuracy bonus is dependent on the remaining duration of the spell, which is determined by spell power. Casting it repeatedly will also extend the duration, however. While short blades are already very accurate, this is a fairly cheap spell, and missing less often means fewer turns wasted in combat. Sure Blade's effect ends immediately if you unwield the affected weapon for any reason.
In 0.17 this spell was removed.