You can use this talent once per battle, plus an additional number of times per day equal to your Charisma modifier.
As a free action before you make a paladin melee attack roll, you can declare that you're using a Smite Evil attack. Add +1d12 to the damage roll AND deal half damage with the attack if it misses.
Your Smite Evil attacks gain a +4 attack bonus.
Add 2d12 to the damage roll instead of 1d12.
Add 4d12 to the damage roll instead of 2d12.