What Dumbledore wanted was for Harry to believe he had to die, in order for Harry's “sacrifice” to give the same power of protection to the defenders of Hogwarts that Harry had gotten from his mother.
Dumbledore was also aware that he wouldn't be alive for long because he had been cursed by the Horcrux ring. Instead of suffering a painful death, he urged Snape to end his misery.
The foremost reason of why he had to die was his past obsession with deathly hallows. He carelessly touched Marvolo's ring , which resulted in hs being affected by Voldemort's curse. Snape clearly told him that it is a curse that will spread with time. So he only had a year to live.
In the sixth book, Dumbledore dies when facing Severus Snape on top of the Astronomy Tower, as Harry helplessly watches from concealment.
While conferring with Snape about the curse, he also asks that Snape kill him when the time is right. Not only would this protect Draco from irreparable harm, but it would ultimately prove his loyalty to the Dark Lord.
“Dumbledore didn't want to lose his wand at that point and Draco disarmed him. So that meant that the wand gave Draco its allegiance, even though Draco never knew it, even though Draco never touched it. “From that moment on, that wand gave its allegiance to Draco, and it wouldn't work as well for anyone but Draco.”
In the [Deathly Hallows] book, Snape's dying words to Harry were "Look at me". Right then we did not realize the significance of his words but in the very next chapter when Harry goes through Snape's memories in the Pensieve, he comes to know how much Snape loved Lily.
Snape tells Harry that he, Snape, is the Half-Blood Prince, and that Harry should not use his own spells on him, as Harry's father did. Harry dares Snape to kill him and calls him a coward once more.
In the novels and per the plan, Dumbledore is killed by Snape during the Battle of the Astronomy Tower. In the following days, a funeral is held for the Hogwarts headteacher down by the lake, attended by all students and teachers (excluding Snape).
Gaunt's ring
After retrieving the ring Albus Dumbledore himself fell victim to a curse that, even when contained, would likely have killed him within the year. Once rendered defunct as a Horcrux, the stone was placed inside a Golden Snitch and left to Harry Potter in Dumbledore's will.
Dumbledore reveals how thoroughly he loves Harry. Harry is brave, and Dumbledore is proud as any father would be. More than that, Dumbledore succumbs to a parent's weakness; he cares more about Harry's happiness and wellbeing than the wizarding world he is trying to protect.
Since the curse spread from a ring which Dumbledore put on a finger, the curse was strongest on his hand which started to rot first. So even if Dumbledore cut off his hand, the curse would simply manifest itself on a different part of his body.
Because he had entered the realm that serves as a gateway between life and death; Limbo.
Voldemort told Snape he had been a faithful servant, but that he had to regrettably kill him, as he mistakenly believed he was the master of the Elder Wand, as Snape had killed Albus Dumbledore, its former owner the year prior, during the Battle of the Astronomy Tower.
In her estimation, in an attempt to protect the true Harry's identity, Snape sacrifices Hedwig, thus keeping the other Death Eaters off his scent albeit for only a short time.
Now, as firmly established, Snape was not the greatest fan of Harry, but that didn't mean that he ever stopped loving Lily. Dumbledore was surprised that Snape seemed to care for the boy. With a swish of his wand, Snape conjured up a Patronus – Lily's Patronus, a doe. 'Always,' he said.
Image via Warner Bros. Similarly to Harry, Snape's patronus represents a person. In the memories he gives Harry before his death, Snape shows Dumbledore his patronus, using the form to prove his love of Lily Potter, Harry's mother.
Originally Answered: Why did Dumbledore plead with Snape? Dumbledore knew Snape didn't want to kill him and was afraid that Snape would still refuse to do so, and would then be killed by his Unbreakable Vow.
Snape's secrecy is revealed to have been a mask and he has sacrificed being well-liked to be able to save Harry, all because of his love for Harry's dead mother: the only friend Snape ever had.
Draco Malfoy's mother Narcissa was cold, cunning and devoted to the Dark Lord. But she was also a mother, which meant she was willing to risk everything to make sure her son was safe. When Harry survived Voldemort's Killing Curse for the second time, Narcissa pretended he was dead so she could get to Draco.
Severus Snape is one of the most divisive characters in the entire "Harry Potter" series. He was a double agent, so many character details were kept a secret. His mother was a witch and his father was a Muggle, leading to the moniker "The Half-Blood Prince."
Warner Bros. Harry kills Voldemort during the Battle of Hogwarts, and the villain's last sounds are a scream of pain as he dies. In the book, his last line is "Avada Kedavra," which he casts at Harry before it rebounds and kills him instead.
"The first thing Snape asks Harry is "Potter! What would I get if I added powdered root of asphodel to an infusion of wormwood?" According to Victorian Flower Language, asphodel is a type of lily meaning 'My regrets follow you to the grave' and wormwood means 'absence' and also typically symbolised bitter sorrow.
"Avada Kedavra!" The curse Voldemort spews doesn't work, of course: Harry triumphantly defeats the villain, who killed most of the other people on this list. Photo: Warner Bros.