[return1]

i think nano/raiblocks currency can do that. and there may be others too

however what you are asking is not a requirement - all online transactions will wait for an internet connection before actions can be taken, and this is true even today for physical goods - the paperwork must match before products can be moved.

[saryant]

Things have changed in recent years, but for decades retailers have sold goods without knowing if payment would clear—they accepted checks.

[return1]

that is not a responsibility of the currency however. you can build a trust system on top of the 'transactions layer'