Genesis 18:15

15. She was afraid The direct response to her thoughts, the searching words, the implied rebuke, the evidence from the words that the speaker was Jehovah, all this filled her with a sudden amazement and terror, and under the fear of the moment she denied, saying, I laughed not The denial was immediately silenced by the answer, Nay, but thou didst laugh; and we may well believe that doubt was changed to faith, and Sarah also believed the promise, and, as Kurtz observes, was “thus rendered capable to become the mother of the promised seed . ”