Why is Elizabeth described as a faithful woman in the final scene?

Elizabeth is Hooper's fianc©e. She is
generally described as a kind-hearted and loving woman. When Hooper adopts the black veil and
refuses to take it off, much of the town turns away from him in fearexcept for Elizabeth. She
remains by his side for a long time and tries her best to be cheerful even if she finds the veil
morbid; but even she has her limits.

When Hooper refuses to ever take off the
veil, even when they are alone, Elizabeth wonders why. Hooper tells her the veil represents the
secret sin which all people hide. Just then, Elizabeth becomes as disturbed by the veil as
everyone else. She leaves Hooper, breaking off their engagement, since he would rather make the
existence of his dark side plain than hide it beneath a guileless mask.

Elizabeth never marries. Even though she avoids interacting with Hooper directly, she
still inquires after him to make sure he is doing well. So, even though Elizabeth is technically
single, she is still connected to Hooper. She still loves him, despite knowing about the
existence of his secret sins, even though she is not willing to marry him and be part of his
daily life.

When Hooper is on his deathbed, Elizabeth rushes to his side, and
it is here where the narrator calls her "faithful." Even though she does not
understand Hooper, she still loves him and never gives her heart to anyone
else.