"There is a major issue of trust," said Jeroen Dijsselbloom, the Dutch Finance Minister who heads the 19-nation group of countries sharing Europe's single currency. "Can the Greek Government be trusted to do what they are promising in coming weeks, months and years?"
Some figures believe a deal is possible, but others are sceptical Greek Prime Minister Alexis Tsipras will deliver on his promises.
Since their election in January, Tsipras and his Finance Minister Yanis Varoufakis have stunned conservative Brussels with their way of doing business.
They conducted endless talks in what their negotiators across the table began suspiciously to view as ideological brinkmanship.
Tsipras and Varoufakis - now ditched - apparently believed time was in their favour and as deadlines loomed, the creditors would fold so they could get at least some of their money back.
While demanding solidarity from their partners in Europe, the duo were unashamedly populist back home, telling Greeks they would never have to make further sacrifices, and blasting austerity demands as "blackmail". "terrorism" and "fiscal waterboarding".
The moment that changed everything was on June 26 when Tsipras walked out of negotiations over terms for help, just a few days before he needed cash to repay money to the IMF, and staged a snap referendum.
The plebisicite delivered an emphatic "No" to the bailout conditions, an act of popular defiance that Tsipras forecast would lead to a climbdown by the creditors and an end to the banking crisis. The tactic backfired disastrously. The Greek economy went into a death spiral, with the final impact prevented only by support by the European Central Bank. Tsipras has now humiliatingly agreed to the same terms that he had so loudly rejected, but coupled this to an 80 billion request to ease debt and buttress the economy over the next three years.
Hardliners are demanding his Government immediately start implementing market-oriented reform, under close scrutiny from outside to prevent delay or subterfuge.
"In the last months, hope has been destroyed in an incredible way, even up to just a few hours ago. Definitely we cannot trust promises," German Finance Minister Wolfgang Schaeuble said at the start of an emergency meeting of eurozone finance ministers.
Another hardliner is Finland, where euroscepticism - fuelled in part by the Greek debacle - is flourishing. Its Foreign Minister, Timo Soini, has branded Greek bailouts as "a moral hazard and a pyramid scheme that will continue as long as the milkmaid has a cash cow to milk".
A more conciliatory tone is being struck by France and Italy, who see Tsipras' climbdown on pension cuts, tax hikes and the sale of state assets as big concessions, and fear a 'Grexit' could damage the EU's economy and torpedo the project of European integration, of which the euro is the keystone.
The United States, meanwhile, is warning of the ripple effect on security should Greece collapse and join the list of ungovernable states. In the end, say some commentators, dread of chaos may trump suspicion of Tsipras, tilting the scale in favour of a deal.
'No' voters stunned by u-turn
On the streets of Athens and in tavernas on the islands, many ordinary Greeks were dumbfounded over their Government's spectacular u-turn after they gave international creditors a bloody nose.
They will now have to accept a package that is even harsher than the one that was rejected in the referendum, to the tune of about 4 billion.
"I voted 'No'. And of course this new proposal doesn't correspond to that 'No'," Vassilis Sika, 20, who is unemployed, said in Athens. "I feel like a slave. They do what they want, and we can't participate."
The sentiment was echoed by Marios Rozis, a 23-year-old speech therapy student. "Everybody was happy [last week], it was a mature decision against austerity," he said. "Today, I feel the referendum happened for no reason."
A cartoon in the Kathimerini newspaper summed up the swift change in the public mood: a group of Greeks joyously cheering "No" last Monday next to a shot of the same group later in the week collectively gasping "Oh No!".
There was particular bitterness on Greece's islands, which for years have enjoyed VAT breaks and subsidies. Those will now be scrapped, leading to increased costs for islanders as well as international tourists.
- additional reporting Telegraph Group Ltd
