The way the Wish system is first explained to players is a tad confusing if not slightly misleading. The game tries to explain it so that players will always want to Roll/Wish 10x as once, because if they do they’re guaranteed at least one 4-star Weapon/Character. And, this is true. But, players don’t have to only wish 10 fates at a time, they’ll get a 4-star at least for every 10 rolls, no matter if it’s consecutive or individual.
This Pity system also applies to 5-star rewards in that, if players don’t get a 5-star in 89 rolls, they 100% will on the 90. Additionally, if players get a 4-star somewhere before their 10th roll, the count restarts. Don’t be like one of those players who spends thousands just for one character.