Rosalind in John Wyndham's The Chrysalids has to deport herself in public in a way such that she does not reveal her mutant powers of telepathy. The external Rosalind, the public Rosalind, is forced to show adherence to the norms and to seek and destroy plant and animal mutations just as vigorously as the other inhabitants of the rigid land of Waknuk do. Privately, in her inner, or "real" self, Rosalind has the mutated ability to communicate with others telepathically.
She is a member of a small group of mutants in Waknuk who have developed telepathy, which, as far as the land of Waknuk is concerned, is a deviant mutation that must be snuffed out. By contrast, the land of Sealand (New Zealand) is populated by hosts of telepathic mutant humans who save the telepaths of Waknuk, destroy rigid and unchanging Waknuk, and invite the young telepaths from Waknuk to help build a new world.
"(Rosalind) was in a hostile world, and deliberately equipped herself to face it"
Rosalinds knows that the world is full of threats but she put up a strong front and disguises herself with a though facade. She "builds her own convincing creation" when she was a "sensitive, fearful, yet determined child” . This also shows that Rosalind is very self-reliant and depend on herself to source for weapon and protect from threats.
When the Spider-man says he will take Rosalind as his lover, “(Rosalind’s) eyes dropped” but “it was not surrender to the stronger character, the conqueror. It was loathing, a horror which broke her defenses from within.” à Rosalind is terrified and is made to be described a ‘child’ in the face of the thought of bearing Spider-man’s child. She had lacked the physical and emotional strength against a stronger character like Spider-man and she breaks down and exposed her possibilities of being harmed.
Therefore, Rosalind appears to be though on the outside (external) but is vulnerable in the inside (internal).
Source: My personal notes ;)