The Wide Saragasso Sea is referenced as the books title. It is set in the 1830's-1840's after the Emancipation Act of 1833, where the slaves were freed. Rochester marries Bertha for money and overlooks how drastically different their lives are. There was alot of trade that crossed to and from the Saragasso Sea- one of the most obvious being slave trading. So when it was abolished, her family was targeted due to her late father being a cruel plantation owner. They are separated by the Wide Saragasso Sea; which also means cultural differences. For example, Rochester is used to "respectful English servants" whereas Christophine, Berthas servant, speaks her mind and gives an attitude to Rochester. She also have connections to the obeah spirituality of the islands where she is from- this is something Rochester dosen't understand due to that not being the culture in England. When he took her to England he took her away from anything she ever knew and isolated her even more. I feel like the Saragasso Sea acts as a metaphor for her isolation and loss of identity. It also shows a racial in-betweenness due to being caught between her Caribbean heritage and her English ties. Due to the seas reputation for being mysterious and a difficult journey to take-I feel like it connotes to Rochester and Bertha feeling trapped my societal standards and marriage patriarchy.
https://oll.libertyfund.org/publications/reading-room/Wilmeth_Rhys_Sargasso_Sea