If given the comparison for both Diaz’s and the Aztec elders account, Diaz account is written in memoir while the Aztec elders tone is extremely confident.
Moreover, Diaz tone of memoir reflect the author’s knowledge of what is to come where it contain more fear and uncertainty so he could not afford to be confident.
Meanwhile, the Aztecs response is more confident for they were extremely wealthy as it reflected in the author’s knowledge.