Sorry for my ignorance but could you explain what TVS stand for and what it means? xD Thanks
Sure, mate. TSV stands for Trainer Shiny Value. It's a random 4 digits number, generated when you start the game and will stick will you for the whole game (unless you restart the game, then your trainer ID will be resetted and you will get a new TSV). TSV can be 0001, 0023, 8999, etc... a lot of people can have their TSV matched.
Now I'll explain how TSV work. Every time you got an egg (receiving via a trade, NPC, breeding), each egg has its own ESV (egg shiny value), also a 4 digits number. When your TSV and the ESV matched and you hatch it, the egg will always be hatched shiny. And it's always be legit (where do you think the 6IVs shiny mons come from?)
To know your TSV, go to the link I post above and ask people in that thread, they will help you