The current Conservative leader Kemi Badenoch was trade secretary in Truss's government in 2022.
Stride - who was a key ally of Sunak when he was PM - will say it will take time and honesty for the Conservatives to rebuild trust with voters.
"So let me be clear: never again will the Conservative Party undermine fiscal credibility by making promises we cannot afford," Stride will say.
In a furious response, Truss argued her economic plan "provided the only pathway for the Conservatives to avoid a catastrophic defeat" in last year's general election.
Truss added: "As it was, Mel Stride and too many fellow travellers in the Conservative parliamentary party supported an economic policy that backed high immigration, raised taxes to a 70-year high and pursued unaffordable Net Zero policies - and the electorate delivered a devastating verdict on that record last summer.
"Until Mel Stride admits the economic failings of the last Conservative government, the British public will not trust the party with the reins of power again."
In his speech, Stride will also take aim at Reform UK and its leader Nigel Farage.
Last month, Farage - whose party is leading in national polls - set out plans to restore the winter fuel allowance, scrap the two-child benefit limit and lift the salary level at which people start paying income tax to £20,000.
The shadow chancellor will say Reform's "economic prescription is pure populism".
"It doubles down on the 'magic money tree' we thought had been banished with Jeremy Corbyn," Stride will say.