Just want to add that it's successful negotiations, AND you can choose to spend diamonds to make them successful IF you have failed on the basic 3 tries (ie: you've run out of initial "free" configurations attempts).
As well, you can always surrender, and try that negotiation again, with a fresh 3 chances, and spend goods on retry.
However, just note that the "EXTRA TURN", offered in the Tavern (essentially giving you 1 more "try" than the normal 3 (ergo: 4) is NOT enabled for GbG.
The tavern extra turn features only works in GE negotiations.