Question Concerning Diamond Requests in the Spire Event

[Finndelore]

Duringa spire event convince session, I am being told I have turns left but am also being asled for diamonds in order to continue. This seems illogical. Can someone explain the disconnect here?

 

[Jake65]

You'll be presented with a diamond cost if you don't have enough of the required coins/supplies/goods.
In this case your coins are highlighted in red which means you don't have enough.

 

[Jake65]

To make up the shortfall in coins will cost you 59 diamonds.
Cheaper fix is to leave the negotiation and collect more coins or use a coin instant.
You will lose what you used in the first round so always safest to 'check stock' before starting the negotiations.