Theory:

“I have come to bid you goodbye,” he cried.

“Swallow, Swallow, little Swallow,” said the Prince, “will you not stay with me one night longer?”

“It is winter,” answered the swallow, “and the snow will soon be here. In Egypt the sun is warm on the green palm trees, and the crocodiles lie in the mud and look lazily about them.”
 
“In the square below,” said the Happy Prince, “there stands a little matchgirl. She has let her matches fall in the gutter, and they are all spoiled. Her father will beat her if she does not bring home some money, and she is crying. She has no shoes or stockings, and her little head is bare. Pluck out my other eye, and give it to her, and her father will not beat her.”

“I will stay with you one night longer,” said the swallow, “but I cannot pluck out your eye. You would be quite blind then.”

“Swallow, Swallow, little Swallow,” said the Prince, “do as I command you.”

So he plucked out the Prince’s other eye, and darted down with it. He swooped past the matchgirl, and slipped the jewel into the palm of her hand.
 
“What a lovely bit of glass!” cried the little girl; and she ran home, laughing.
Explanation:
 
Swallow informed Happy Prince that it was time to bid goodbye. After hearing the swallow’s farewell, Happy Prince requested him to stay with him for one more night. The swallow informed the Happy Prince that the winter season had begun and would snow after some time. The weather in Egypt was hot, and even the crocodiles were lounging in the dirt. As a result, he advised him to allow the Happy Prince to travel to Egypt.
 
After hearing that, the Happy Prince claimed that there lived a small girl whose matchsticks had fallen into the gutter (sewage) and gotten wet. So she couldn’t sell her match sticks since they were all spoiled, and she wouldn’t be able to make any money. If she returns home without money, her father would become enraged and beat her. While thinking about the situation, the girl started crying.
 
shutterstock_1988151536.jpg
A crying poor girl
 
Furthermore, Happy Prince said that the little girl was not wearing shoes or stockings and had not covered her head. She was very poor. So he told the swallow to take out his other eye. In addition, he asked the swallow to give it to her so that her father doesn't beat her. The bird agreed to stay with him for one more night, but he refused to take out another sapphire because if he did that, then Happy Prince would be blind. Later, the Happy Prince told the swallow to do what he had ordered him.
 
At last, the swallow obeyed the Happy Prince’s order. The bird took another stone from the Prince’s eyes and flew near the little girl. When the bird saw the little girl, he bent very low and put the sapphire stone on the little girl’s hand. On seeing the sapphire, the little girl felt delighted and ran home happily.
 
Meanings of the difficult words:
 
S.No
Words
Meanings
1
Palm A tree that grows in hot countries and has a tall trunk with a mass of long pointed leaves at the top
2
Pluck Take hold of something and quickly remove it from its place especially of a bird rush downwards through the air
3
Swoop To slide without intending to
4
Slip To go somewhere or put something somewhere quickly, often so that you are not noticed
Reference:
National Council of Educational Research and Training (2006). Moments. The Happy Prince – Oscar Wilde (pp. 28-35). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.