Hermione used a strand of Bellatrix's hair, which had fallen onto her jumper when she and the others were being held at Malfoy Manor, to disguise herself as Bellatrix with Polyjuice Potion.
Bellatrix wrote it on Hermione so that Hermine wouldn't forget her heritage, and Bellatrix is completely insane, that is a fact.
In Harry Potter and the Deathly Hallows: Part 1, Bellatrix used her knife to carve the word "mudblood" into Hermione Granger's arm. The film version of the knife bears a resemblance to cross-shaped spearheads that leave a hard-to-heal wound.
Bellatrix Lestange tortured Hermione because she thought that the sword from Godric Gryffindor was stolen from her vault and she wanted to know how that was possible. She used Crucio and also cut Hermione spelling the derogatory term for muggleborns into her arm.
The cup, which was made a Horcrux with Hepzibah's death, was left with Bellatrix Lestrange who kept it at Gringotts. Griphook and an Imperiused Bogrod helped Harry, Ron and Hermione break into Bellatrix's vault and recover the Horcrux. The cup was destroyed by Hermione Granger, using a fang from the Basilisk's corpse.
Harry Potter and the Deathly Hallows
In this book, Rowling reveals that Bellatrix is the guardian of Helga Hufflepuff's cup (though she is unaware that it is a Horcrux), which Voldemort has entrusted the Lestranges to keep in their Gringotts vault.
Harry knows from his conversations with Dumbledore that if a Horcrux is in the vault, it must either be the Hufflepuff cup or else an unknown object, so they have no choice but to look for the cup.
She wasnt madam Pomfrey. Meaning, while she had a general knowledge of various spells, she did not have the expertise in healing specific spells to be able to heal a death wound on a house elf. Their physiology is very different from wizards.
Remember in the last Harry Potter film, when Hermione takes Polyjuice Potion and magically transforms into an exact replica of Bellatrix Lestrange? Well, our real life Hermione, Emma Watson, just did the exact same thing – but on the red carpet.
Voldemort is a master manipulator. By humiliating Bellatrix as he does, he punishes her for her part in the failure at the Ministry of Magic — including her failure to finish off Tonks — and rouses her to try harder to murder members of her family.
Cruciatus Curse ('Crucio')
Harry tried to use this spell himself. The first time was against Bellatrix after she had killed Sirius. His attempt was unsuccessful because, as Bellatrix mockingly explained: 'You need to really want to cause pain – to enjoy it – righteous anger won't hurt me for long…'
Why didn't Harry use Avada Kedavra to kill Voldemort in the final battle? Harry used Cruciatus curse on Bellatrix when Sirius was killed by her. He was in anger, but even that anger was of a pure heart. He had to mean it.
She was what Voldemort wanted to be for she was loved, Pureblood, and an aristocrat as well. He probably saw that and her potential and decided to take her under his wing, to make her his. His possession. He treasured her.
Just like his father, Draco loved to hate on Muggles. He took particular pleasure in taunting Hermione Granger, who just happened to have Muggle parents. Malfoy called her 'Mudblood', a very grave insult referring to a wizard or witch born to non-magic parents.
She made sure HE was safe - putting THEIR LIVES at risk to save his - before they escaped. And yet while Bellatrix tortured Hermione, Draco did nothing. Because he was a weak-willed fraction of a human being who deserves nothing but contempt.
Obvious spoiler warning! Yep, that happened: Bellatrix and Voldemort had sex sometime around Order of the Phoenix or Half-Blood Prince, and their wild night in bed led to a child named Delphi Diggory/Riddle/Lestrange. According to Delphi herself, she was born sometime before the Battle of Hogwarts.
The pink dress is a shorthand, and indicates to the reader that Movie Hermione is stepping out of her comfort zone. And it's worth noting that the filmmakers did the reverse in DH. Book Hermione wears a lilac dress to Bill's wedding. Whereas the filmmakers dressed her in bright red, which is more of a power color.
She likely was attached to her wand, and didn't want to give it up. The Dark Lord could relatively easily get a wand, and she probably didn't want to part with hers. In addition, if she did give it up, it'd mean she would be in the midst of a wizarding war with a less-than-optimal wand.
In the Cursed Child we find out that Bellatrix and Voldemort had a daughter, which means that Bellatrix would have been pregnant during the books.
Why didn't Harry use magic to bury Dobby? Dobby was a dear friend to Harry, so he wanted to provide him with a proper burial. Hence, he refused to use magic to bury him.
And this is why Hermione does not fit into Ravenclaw, since she lacks their creativity of thought. When you also add in her fearlessness and her strong convictions about right and wrong, which are inherently Gryffindor traits, then there was even less of a chance she'd end up wearing blue and bronze.
Snape was full of venom, not just bleeding out, and sealing the wound would only have prolonged his death, The Trio had also used up their supply of dittany on treating their own burns earlier in the day.
Bellatrix Lestrange
Ollivander described this wand as "unyielding" a very telling feature of the owner as well. Legend has it that there was a European superstition warning not to grow anything near a walnut tree because it contained evil or poison-also in the walnut-wood wand of Bellatrix.
Following that incident, Severus Snape passed the counterfeit sword to Bellatrix Lestrange. Bellatrix then stored it in her Gringotts vault alongside Helga Hufflepuff's cup, one of Voldemort's Horcruxes.
Unknown date, 1946: Tom Riddle murders Hepzibah Smith, sending a piece of his soul into Helga Hufflepuff's cup. It becomes the third Horcrux. (Riddle also steals the Slytherin locket.)