Help Manga search - Fantasy - Coin or Medal hidden in sword is worth a lot

[Isekai_4_life]

So ive tried google, chatgpt, and various other sources. No dice. I don't ask these questions lightly.
It's a fantasy. Some guy move into a house by a lake city or something. He buys a slave who was a fallen knight or noble. On a shopping trip she take interest in a weapon in a window. the MC buys it for her but she refuses to use it to fight. Later on it's revealed there was a coin or medal hidden in the weapon that's worth a huge amount of money. Also, (though I could be confusing this with anouther manga) he has to confront the guardian deity of the lake, a sea dragon of some kind i believe.

help plz, ive been pawing though manga titles for over a week looking for this.

 

[Reiru]

So ive tried google, chatgpt, and various other sources. No dice. I don't ask these questions lightly.
It's a fantasy. Some guy move into a house by a lake city or something. He buys a slave who was a fallen knight or noble. On a shopping trip she take interest in a weapon in a window. the MC buys it for her but she refuses to use it to fight. Later on it's revealed there was a coin or medal hidden in the weapon that's worth a huge amount of money. Also, (though I could be confusing this with anouther manga) he has to confront the guardian deity of the lake, a sea dragon of some kind i believe.

help plz, ive been pawing though manga titles for over a week looking for this.

Might be this one,
https://mangadex.org/title/24e5f5b0-c14b-4597-bb0a-606c583a657c/argate-online

The lake side house in early chapter 14-17, and the deity guardian also in chapter 17.

Chapter 19 MC buy the slave,
Chapter 20 he found the coin thing inside the weapon.

 

[Isekai_4_life]

Thank-you. I thought for sure I had a ready looked at this one. it's been driving me crazy for a week or more.