Emigrated to USA in 1906.
Bertha Sarah and Alice (both of Malvern) travelled together from Liverpool in 1906 on the Celtic and were processed on Ellis Island, NY, on 8 July 1906. New York has a death record for Bertha.

MAL Crawshaw writes:
When we were in New York in 1958, an EB took us to see a relative of mine in the hospital. There we saw a frail little old lady whose name was Roberts. She claimed she was the grand-daughter of JLK, but she did not seem to know anything about my grandfather Alfred.

J Crawshaw replies:
JLK had 10 kids, 5 of whom died in childhood. Frank and Alfred were well down the order. The eldest was Fanny Adela Jane or Adela Frances Jane, according to which version you prefer, b. 1848 in London, d. 1928 at Chelmsine (though how this squares with her daughter's implied assertion that she ended her days in Africa, I do not know). She married a fellow called Geyden-Roberts and had no fewer than 8 daughters.
The youngest of these, Grace Ermyntrude [I think we have misspelled the name] b. 1886 in Kingston-on-Thames, married Ed. Clist in Wellington Somerset in 1910 and had 3 children. Grace Ermyntrude wrote the famous screed and her elder sister Frances Emily G.-R. (b. 1875 Scotland-d. 1964 Chelmsyne; so the G.-R.s stayed on in the Wellington/Chelmsyne area long after the death of JLK in 1899 and of his widow two years later) seems to have made a note in it.

We know no more about Grace E. (though it would be most interesting to trace her offspring). The most likely candidate for your meeting is her elder sister Bertha Sarah G.-R. b. 1878 who migrated to Connecticut USA in 1907. In 1958, she would have been 80. May have been unmarried, or in any case have been using the name Roberts. In any case, she would have been a grand daughter of JLK. How did whoever introduced you know she was your relative?

SC notes [2010] that the US census of 1880 shows a Bertha Geyden Roberts aged 3 years, born in Massachusetts. Father is John H Roberts, born 1851 in ME, mother was from Nova Scotia.

The land o’ dream by Bertha Geyden Roberts (verse published in Connecticut, 1927) [Doubtful]