Here is the proof of Sariah's comfort. Lehi says words of comfort to her, but Sariah is not comforted until she has seen her sons return safely. Perhaps Nephi does not tell us more, perhaps Sariah really was comforted by Lehi. Regardless, the picture painted here of the grieving mother, the caring (but in this case helpless) Lehi and the continuation of tension until her sons return, is a completely believable picture of a very human, and very devoted mother.