Theory:

     The poet sat down beside him, and he and Ernest talked together. Never before had the poet talked with a man like Ernest, so wise, and gentle, and kind. Ernest, on the other hand, was moved by the living images flung out of the poet’s mind.
 
     As Ernest listened to the poet, he imagined that the Great Stone Face was bending forward to listen too. He gazed into the poet’s eyes.
 
     “Who are you, my gifted guest?” he asked.
 
     The poet laid his finger on the book that Ernest had been reading.
 
     “You have read these poems,” said he. “You know me, then, for I wrote them.”
 
     Again and again, Ernest examined the poet’s features; he turned towards the Great Stone Face then back. He shook his head and sighed.
 
     “Why are you sad?” inquired the poet.
 
     “Because,” replied Ernest, “all through life I have awaited the fulfillment of a prophecy, and when I read these poems, I hoped that it might be fulfilled in you.”
Explanation:
 
The poet was ecstatic at the chance of meeting him (Ernest). He hasn't yet revealed his identity to Ernest. On the bench, he sat next to him. They started talking on that bright and beautiful afternoon. Despite the fact that the poet had heard about Ernest previously, he had never seen him. The poet enjoyed their meeting because it fulfilled his expectations and delighted him. This is likely due to the poet's lack of experience conversing with such a gracious, intelligent, and benevolent individual. Ernest, on the other hand, was stunned as he listened to the poet's talk.

Ernest had the distinct impression that The Great Stone Face was listening to him as he began speaking with his visitor. The poet's words had a profound effect on him, as his words reminded him of his beloved mountain. This prompted him to inquire about his adored visitor's identity.
 
At that point, the poet decided to disclose his true identity. He pointed to the book Ernest was holding and introduced himself as the book's author.

Ernest inspected him, comparing his features to the Great Stone Face as soon as the poet revealed his identity. As his confirmation surprised him, he conveyed his discontent with his current predicament with a sigh and a shake of his head. It was understandable that he was taken aback. It's because the final result was disappointing. The face of the poet did not match that of the Great Stone Face.
 
Ernest has been waiting for a person who looked like The Great Stone Face for all of his life. His wish for the prophecy to come true was yet to be fulfilled. Over the years, Ernest was captivated by the poet's poems because they convinced him that he had finally discovered the ideal person he had been searching for. It made him (Ernest) believe that the poet was the one he had been looking for all these years. However, not even the poet was able to meet his expectations.

Ernest described the situation to the poet when asked why he was unhappy. Ernest had high hopes for the poet, believing that he would be the ideal match for the legend told by his mother. He was disappointed since his hopes had been crushed.
 
Meaning of difficult words:
 
S.No
Words
Meaning
1.
Flung Throwing out or get rid of something
2.
Examine To check or observe something carefully
3.
SighedA deep audible breath showing your disappointment
4.
Featurequality or a part of something
Reference:
National Council of Educational Research and Training (2008). Honeydew. The Great Stone Face II - Nathaniel Hawthorne (pp. 128-132). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.