Sarah Wentworth (née Cox; 1 January 1805–14 July 1880) was an Australian proprietor and businesswoman who brought the first breach of promise suit in Australia.

Payne, who vowed to Sarah "that his eyes might drop out of his head if he did not fulfil his promise of marriage," cheated on her with a wealthier widow by the name of Mrs. Leverton, following which Cox sent him a volley of invective-filled letters.

[2] Carol Liston, biographer of Sarah Wentworth, noted that her commissioning of various domestic duties was fundamental to the success of her husband and children.

The controversy flared over May and June, before the women indicated to Lady Mary FitzRoy, wife of the governor, that they would not attend functions at Government House and apologised for what had occurred.

[7] As early as 1831, following the death of Sarah's father, Francis Cox, William Wentworth intended to have land consecrated and to build a family vault at Vaucluse.

This did not eventuate in his lifetime but Wentworth had informed his family that he wished to be buried near a rocky outcrop on the hill above Parsley Bay.

[7] After Wentworth's death at the family's rented estate, Merley House, Wimborne, Dorset, England in March 1872, Sarah Wentworth sent her son-in-law Thomas Fisher a sketch of the location and instructions that a vault was to be hewn out of a large single rock on the slope but "left in its natural state outside".

Sarah informed Fisher that she would travel to Brussels to order marble for the vault and would also bring "some Iron gates and railing to enclose it".

The vault was to be large - Eliza wrote: 'it was Papa's wish to have my grandfather, my Uncle & Willie & Bell & poor Nellie & we should all like to be there when our time comes.

Despite her desire for the family to "all rest together in our native place", Sarah was buried in July 1880 in Ocklynge Cemetery at Eastbourne, Sussex.

[2] The Wentworths had seven daughters and three sons:[6]:24-25 Writing about her lawsuit, Alecia Simmons in The Sydney Morning Herald in 2008 described then-Sarah Cox as "a fiercely independent 18-year-old".

Referencing this, Grace Carroll writes:Although William Charles Wentworth continues to be heralded as a significant figure in Australian history, Sarah's story has not been forgotten.