of Ukraine and said Beijing would face consequences if it did not "play by the rules".
Even her supporters fear she could be too quick with opinions to be an effective diplomat, especially her comment on Macron.
But much of her performance so far was crafted for a particular electorate, the Conservative Party, and some supporters say while she will be tough, she will also be measured when she takes the reins of power on Tuesday.
WOODEN?
Her appeal, even her most reluctant supporters say, is that she is dynamic, a workaholic who is across the detail of policy. Others believe she can steady the ship after Johnson's turbulent and scandal-riddem three years in power.
Beyond tax cuts funded by more borrowing, Truss has said she will set out immediate action in her first week to tackle rising energy bills and to increase energy supplies.
But it is perhaps her stance on Brexit that had the biggest impact.
Despite voting to remain in the European Union at a 2016 referendum, Truss has taken a hard line over Northern Ireland trade, to the delight of eurosceptics and the dismay of Brussels which says it breaks international law.
One of her biggest weaknesses is what one Conservative lawmaker describes as her not being the "most effective communicator", characterised as being a "bit wooden" by Ed Costelloe, chair of the group Conservative Grassroots.
At a debate, she admitted she might not be "the slickest presenter" but "when I say I'll do something, I do it".
($1 = 0.8698 pounds)
(Reporting by Elizabeth Piper; Editing by Kate Holton and Alison Williams)