Elisa Bianco said she had just months to live and Sally Retallack funded a Â£2,500 final trip for the 22-year-old, London's Appeal Court heard.
Bianco, of Station Road, Fowey, Cornwall, was jailed for 32 months at Truro Crown Court in December 2015 after she admitted stalking.
Appeal Court judges cut the sentence to 28 months.
Bianco met Mrs Retallack, 49, while a 16-year-old student at Cornwall College in St Austell.
She told Mrs Retallack she had been given three months to live.
Mrs Retallack ended up taking Bianco into her family home and cooked and cared for her, the court heard.
She discovered her deceit but Appeal Court judges said Bianco's fantasies had taken a "truly devastating" toll on Mrs Retallack, who had moved abroad to "try to rebuild her life".
The appeal judges said Bianco's sentence failed to reflect her guilty plea, deep remorse, and the steps Bianco has taken to find and hold down a job.
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