Lorne was quite certain, because that's how it was written in the original work.
Peter Pettigrew is a cowardly opportunist who always prioritizes the "most comfortable option at the moment" and never plans ahead. Only when danger is truly looming in front of him will he completely break down and run away.
While Sirius escaped from prison, Peter Pettigrew was still seen as a selfless hero in the public eye, which might give Peter a false sense of security—what if Sirius were captured by Dementor or the Ministry of Magic without explanation?
Another point is that he has nowhere to escape. He needs the Weasley family ' protection. If Voldemort's remaining followers find out he's still alive, they certainly won't spare him. And the rat's Animagus form is too weak; even a Kneazle could easily kill him.
He might slip away from Ron briefly, hiding under the bed or in the sewers for a while, but he wouldn't dare stray too far from the Weasley family.
I really want to see Ron's expression when he finds out his Scabbers is a short, fat guy.
Thinking of this, Lorne couldn't help but laugh out loud.
Sirius thought Lorne's laughter was one of confidence and certainty, so he ignored everything else, grabbed the teapot from the table, filled all the cups, and drank them one by one after they cooled down. He then turned around and began to gulp them down.
Lorne was taken aback by his display. "What are you doing?"
"Hydrate," Sirius's lips were still parched, but his withered face and tangled hair gave his words a semblance of credibility. "It would be even better if we had some food."
Lorne gave a curt snort, "Just you wait."
When Lorne recalled that Harry had first come to his shop for a late-night snack, Lorne suddenly felt a sense of order, as if fate had indeed ordained it this way.
Whether it was the residue from the Soul-Healing Potion that worked, or a meal that quickly restored Sirius's humanity, he can now sit steadily in a chair, provided he doesn't mention what happened back then.
Lorne, of course, knew the inside story.
When Voldemort targeted the Potter family, James and Lily used the Secret Keeper Spell to hide their home. James trusted Sirius, Sirius, putting himself in their shoes, suggested changing the Secret Keeper and recommended Peter Pettigrew, spreading the word that he was the Secret Keeper, thus providing cover.
But little did they know, Peter Pettigrew had already sided with Voldemort, betraying Harry's parents and leading to their murder by Voldemort.
After the plot was exposed, Sirius realized Peter's betrayal and went to intercept him. During the standoff, Peter used a spell to kill twelve passing Muggle, cut off one of his own fingers, and then transformed into a rat and fled. Sirius, believing Peter be dead, had no more attachments and did not plead for himself, content to spend the rest of his life in Azkaban.
If it weren't for the Ron family winning the lottery and getting their story published in the newspapers, Sirius would probably still be punishing himself in Azkaban.
"I will help you hide, cover for you, and even help you capture Peter Pettigrew," Lorne stated his ultimate goal, "The price is that you will work for me after Peter's death."
"I'll do anything to kill him." Sirius's voice was calm, but every word was resolute.
"Don't you have any conditions?" Lorne asked in surprise.
"Can I make any more demands?" Sirius asked, surprised. "Then I want to kill him myself, making sure he's 100% dead."
"Sure," Lorne readily agreed.
Sirius looked around the Magic Mobile Phone shop and suddenly asked, "Why are you helping me? Harboring criminals could very well shut your shop down."
"Last semester I conducted a truth education program at Hogwarts," Lorne said, one hand resting on the counter. "I believe your story serves as a good test of my work last semester, and as the person in charge of this program, I couldn't just let the real culprit go unpunished when I knew the truth."
Sirius, mimicking Lorne, said, "Looks like you'd make a good teacher."
"Once the truth comes out, you must say the same thing to Dumbledore."
"I will," Sirius, turning his head slightly, "But if you want to win his favor, you might as well give him some unusual candy."
Sirius is staying in Lorne's room for the time being.
He's staying here to avoid trouble for now, and Lorne has promised to let him go to Hogwarts and cause trouble for Peter Pettigrew when school starts.
Lorne didn't have the habit of walking his dog. Apart from bringing Sirius food and water and occasionally taking a few newspapers with wanted posters, he didn't interact with him at all. He even slept on a small bed in the conference room.
One day, Sirius finally couldn't take it anymore. "Staying here is so boring. I hear their laughter every day but I don't feel anything. It's more torturous than Azkaban. Can't you give me a Magic Mobile Phone to play with?"
Lorne extended a hand. "Eight Galleon, eight Silver Sickle, and eight Knut."
"No problem," Sirius readily agreed, "I'll give you more when I get back to the Black family."
Lorne withdrew his hand. "Cash on delivery. Magic Mobile Phone Shop only offers credit; we never extend credit."
Sirius gritted his teeth. "Where am I supposed to get you Galleon right now?"
"There's another way," Lorne said sincerely, "If you become my employee in advance, I'll give every employee a Magic Mobile Phone."
"Then I'll have to call you boss from now on?"
"There's no such rule," Lorne shook his head. "Just complete the tasks I assign."
Sirius couldn't wait. "Then I agree."
He opened his arms, waiting for Lorne to hand it to him. Lorne rummaged in his pocket for a while and pulled out a notebook with neat handwriting.
"Not just anyone can become my employee," Lorne said with an apologetic smile. "I'm sorry, you haven't passed my interview yet."
Sirius was furious, but he still habitually glanced at the contents of his notebook.
" Magic Power Matrix?" Sirius looked at Lorne with confusion. "Is this a new subject that's only come out in the last few years? Or is it something from abroad? I can't teach you this."
"It's not you teaching me, it's me teaching you," Lorne flipped the notebook in Sirius's hands back to the first page. "I'm hiring a teacher who can master the details of Magic Power Matrix inscription. If you want to become my employee, start by practicing Magic Power Matrix."
Sirius cried out, "But I don't have a wand!"
Lorne gave a disdainful look. "Does a long-time graduate of Hogwarts really need a wand?"
Under Sirius's astonished gaze, Lorne used the Silent and Staffless Levitation Charm to retrieve a moonstone slab, and then used the Silent and Staffless Etching Charm to draw a miniature thermostatic matrix on it.
"You can't?" Lorne was overjoyed inside, but his face remained impassive as he mocked, "Then you're probably still a long way from becoming my employee."
Sirius's mouth gaped open. He didn't understand, but he was deeply shocked. The person in front of him, Lorne, was someone he had never heard of or seen before he went to prison. He looked to be no more than a young man, yet his magical level had reached such an astonishing level.
Did he miss out on the wizarding evolution outside of Azkaban?