|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 a +5 to +15 accuracy to all attacks with your currently wielded short blade. While short blades are already very accurate, this is a fairly cheap spell, and missing less does increase your damage output. This effect is lost if you unwield the weapon for any reason.
Sure Blade's power is based on the remaining duration of the spell. Also, recasting the spell will add to the spell's duration. Therefore casting sure blade several times if you have the extra turns can improve the power and duration of the spell.