Thanks for your message, but, like, can you at least say is stronger sword in dungeon...? Or where should i go to find it? (left/right/up/down/farm a lot of money and buy everything in shop...)
There is a locked door on the top-right corner of the map. There is a huge tree leading there. This door will lead you to the sword eventually. And to find the key that unlocks the door, you need to find running shoes and then go to the caves near the place where you found the magic book.
(Now that I write these things down, I sure realize how confusing this game can be. Sorry about that, I try to remember this next time I make a game!)
If you need further help, here's a map of the "outside part", where I have circled the places where you should go and in which order.
(in hindsight I should have made the game's internal map more useful, but I started implementing it a bit too late and it was hard to put any meaningful info there in that point)