The combat system of Kingdom Come: Deliverance is slightly different from typical RPGs, as it is more and more skill-based. You will need to learn the nuances of how to effectively attack and dodge, even if you are at a higher level than the enemy. But at the same time, this is still an RPG, so superior weapons and armor will give you a huge advantage.
So, the best sword in the game can be safely considered the long sword of St. George. Its damage is 72, and if your strength is over 20, you can do over 150 damage! It is also very expensive - it can be sold for 2200 grosz.
The sword is in a chest located northwest of Ledechko in the forest. You can find out the exact location below, which has been highlighted with a yellow marker:
