why does my skill reset each time I go to a dungon, is that a bug or part of the game?
It's a part of the game. If you drop her ideals of Chasity enough a new dungeon gets revealed by one of the men at the inn. There's a side entrance that allows you to keep your levels and start at level 6 of the 11 layered dungeon which will allow you to get through the dungeon much sooner. However it's all a means to trick the player. Doing so will forfeit the end reward which can sell for a very high price depending on
how far you take it with the merchant at the inn to get better prices for your stuff. The best way to dungeon crawl is to get through the dungeon as soon as possible while only picking up items that are along the way. Play on the Slug difficulty and you'll wrack up so many levels so fast that enemies won't be able to harm you. Go into the second dungeon from the beginning and look for the immediate next exit. Get through all the floors as fast as possible while mowing down enemies that get in your way and get the end reward. Sell it only to the merchant at the inn. The merchants in the dungeon will rip you off. They're good for getting rid of excess loot if you've got it, but expect lower selling rates. Also, don't bother stealing from them. Eventually the asshole god of merchants or whatever it's called will strike you down with a bolt of lightning dropping your HP to near zero while you're usually around enemies in the dungeon to fuck you over.
From what I've played so far, the lower her ideals of Chasity get the easier the game becomes in making money. It's a corruption game. All the NPC's are gunning to impregnate her. It's in the sub tittle. Trying to avoid giving up her Chasity for a virgin run is a grind fest. I don't even know if it's possible to do because the game is so punishing.