This is a very broad question, and not worded correctly. Severus Snape killed Albus Dumbledore in the end of the sixth book. Dumbledore had asked Snape to kill him, to save Draco Malfoy's soul because of the Unbreakable Vow that Narcissa Malfoy made Snape take in the beginning of the sixth book since Voldemort had ordered Draco to kill Dumbledore.
(WARNING: SPOILERS) Rowling never makes it expressly clear in any of her books. However, it is likely that Snape already knew that he would be the one to kill Dumbledore. This, after all, is what Narcissa pleads him to promise: That Snape will watch over Draco, that he will intervene if necessary to secure his saftey, and that, if Draco fails to kill Dumbledore, that Snape will do it for him. Now, obviously Snape knows, since he is on Dumbledore's side, that Dumbledore wouldn't ever hurt Draco or put him in harm's way. So that he could honestly promise Narcissa with little problem. Also, because he promises to kill Dumbledore should Draco fail, we can assume that he has already had the conversation with Dumbledore that deals with Snape bringing about Dumbledore's death when the time comes. This allows him to promise truthfully that he will kill Dumbledore. Snape also has a certain prejudice in Malfoy's favor, since he happens to be an exemplary Slytherin student and is good at potions (though this may well be due to grade inflation). Of course he promises to keep his favorite student safe: but what Narcissa doesn't know is that Snape is not agreeing to protect Draco from Dumbledore and the Order; rather, he's agreeing to protect Draco from Voldemort and from bringing about his own downfall. We see Draco's attempts to throw Snape off his track and to get him off of his back throughout the sixth novel, but know that Snape ultimately succeeds and keeps Draco (as) safe (as he can) from "The Dark Lord".
It didn't hurt because he looked at Snape. Professor Quirrel was right next to Snape, and it was Quirrel that made Harry's scar hurt because he was sharing his body with Voldemort. His scar hurt because the Horcrux inside Harry could sense Voldemort and was attempting to leave Harry's body.
No, he's not. He makes the Unbreakable Vow with Narcissa Malfoy, promising to watch over Draco and help him with his task (killing Dumbledore), and to kill Dumbledore himself if Draco can't do it. But he is never appointed godfather to Draco.
kill em.
Yes, he made the Unbreakable Vow with Draco's mother, Narcissa Malfoy, in the "Spinner's End" chapter of Harry Potter and the Half-Blood Prince. He promised to watch over Draco and keep him safe, to help Draco with his task (killing Dumbledore), and to kill Dumbledore himself if Draco couldn't do it.
Snape agreed to make a magical vow called the unbreakable vow. He swore to protect Draco Malfoy.
The Unbreakable vow the unbreakable vow which is when snape makes the vow if he breaks it he dies
She visited him to see if he knew what the Dark Lord wanted her son Draco to do && if the Dark Lord wanted Snape to carry on the task if Draco failed also she wanted Snape to make the Unbreakable Vow && help Draco so he would not be hurt.
In Harry Potter and the Half-Blood Prince, Severus Snape and Narcissa Malfoy performed the Unbreakable Vow. This is the ultimate magical promise, as if Snape chose to break this promise, he would die. Snape promised whilst holding hands with Narcissa and with the Bonder (witness) Bellatrix Lestrange, that he would assist Draco Malfoy in his task of killing Albus Dumbledore if Malfoy struggles or is in danger of failing. Snape obliged willingly, as Dumbledore and Snape has already planned Dumbledore's death.
They never use the unbreakable vow on Hermione, trust me I would know, I have read them 3 times, but in book 6 its used on Severus
Draco's mother makes me promise. She's upset and wants nothing but the utmost protection for her child. She begs Snape to make the Unbreakable Vow and lay his life on the line for him.
Bellatrix,Narcissa, and Severus meet up where Snape took an Unbreakable Vow which was to protect Draco from Harm and perform any task given to him by The Dark Lord, if he fails while doing the task.
In the sixth book Narcissa made the unbreakable vow with Snape, requesting that he protected Draco as he attempted to carry out the Dark Lord's will and, if Draco should fail, complete the task himself (ie. kill Dumbledore). Later, in Madam Malkin's, she is insulted by Harry who makes fun of the fact Lucius is in jail, and responds with a remark about Sirius' death. She and Draco leave the shop, without perchasing the robes Draco was trying on, to go to a different robe shop - 'Twilfitt and Tattings' - where 'scum' like Harry doesn't shop. Draco, who had been trying to get her to leave him alone while they were in Diagon Alley, eventually manages to sneak off on his own to Borgin and Burkes. This is her last appearance in the book.
Snape killed Dumbledore because: 1. Dumbledore was already dying. 2. Dumbledore asked Snape to kill him. 3. If Snape didn't kill Dumbledore, Draco would have had to and Dumbledore didn't want Draco's soul ripped apart on his behalf. 4. Snape made an Unbreakable Vow with Narcissa Malfoy that he would kill Dumbledore if Draco failed to do so. 5. It would land Snape firmly in Voldemort's good books so that Hogwarts would be under the control of Snape and not the Carrows. 6. If J.K. Rowling hadn't killed Dumbledore somehow, the final battle would be postponed for too long.
This is a very broad question, and not worded correctly. Severus Snape killed Albus Dumbledore in the end of the sixth book. Dumbledore had asked Snape to kill him, to save Draco Malfoy's soul because of the Unbreakable Vow that Narcissa Malfoy made Snape take in the beginning of the sixth book since Voldemort had ordered Draco to kill Dumbledore.
snape promises to protect malfoy (you spelt it wrong) because at the time of the unbreakable vow being made, snape is trying to convince bellatrix that he is working for the dark lord, so he does not want her to think he is trying to help dumbledore. Also, snape knows that dumbledore is going to die soon anyway. dumbledore knows malfoy is trying to kill him, so he wants snape to keep an eye on Draco malfoy, and promising to protect him was a good reason to follow him around.