So I was at Manik shop and I threw my sword into this poor guy stable. So, I tried to go into his stable and then I tried to break into the stable to get it. he walked out and I tried to hit him back in and then I accidentally killed him. I am really sorry about this!

In cases like these you could leave something of a compensation such as diamonds for the player or perhaps if you can,try finding a villager with the same trade for mending.Its good you admitted what you did and I'm sure they will understand.