After Speke’s betrayal, Burton sunk into a depression. Isabel represented the only bright spot in Burton’s life. Even though the two had been separated for three years, Isabel remained devoted to Burton. She faithfully wrote Burton long letters every two weeks despite receiving very few in return. She also rejected two marriage proposals, writing that she would marry either Burton or no one.

Burton visited Isabel at her home upon his return to England. Both revealed that they carried photos of each other during their separation. Burton’s sickly appearance shocked Isabel, but she still deeply cared for him. Isabel and Burton wanted to marry. However, Isabel’s mother still stood in the way. She found Burton’s lack of faith especially abhorrent. Isabel tried to convert Burton to Catholicism for the rest of their lives, without success. Isabel wrote a strongly  argued letter to her mother about why she should marry Burton. Her mother still refused to budge. Burton suggested they marry without Isabel’s mother’s approval. Initially, Isabel refused, finding it hard to disobey her mother, despite being 30 years old.

Burton left England to visit family. He hoped this visit would help him overcome his depression and convince Isabel to disobey her mother.