just do /give minecraft:diamond_sword 1 0 {each:[{id:16,lvl:10}]} (for sharp X diamond sword) goes all the way up to 32780

All you need to do is:

/give <username> minecraft:diamond_sword 1 0 {each:[{id:16,lvl:10}]} 

This is for a sharp X diamond sword.

This goes all the way up to level 32780.