[Reborn!] The Vongola Tenth's Fantastic Journey

Has the Tenth Vongola Boss Been Doing His Job Properly Today? Who knows how well he's doing as boss? Somehow, he's ended up transmigrating to another world. Sawada Tsunayoshi: "Wait, transmigrating through time isn't something that gets a rerun... Oh, it's not ten years into the future... Then where am I?!" One moment, high school senior Sawada Tsunayoshi is being put through hell by his Spartan-style tutor as he crams for exams. The next, he's transmigrated to the Realm of the Phantom Moon and landed right on top of his fiancée, knocking her unconscious. The younger version, that is. Sawada Tsunayoshi: "Kiriya-san!!" Vannie Kirihara Yuri, past version, from Wendy's perspective: The culprit who knocked her out with his butt runs toward her with tears streaming down his face like seaweed, as if she's his savior, arms outstretched for a hug. Vannie Wendy: "Who are you?" Sawada Tsunayoshi: "How do I raise my fiancée's affection for me in the past timeline? Help, answers needed urgently!" The past version, whose strength is at the absolute peak x the Tenth Vongola Boss, in his high school days A sequel to the neighboring story, "[Reborn!] The Savior Squad's Archmage and His Retired Life" No outline, just letting my imagination run wild. The otherworld storyline takes up a large part of the novel, and original characters account for 90% of the plot. Reborn! characters other than Tsuna may not appear. One-on-one romance. Any out-of-character behavior is my fault. Theme: Perseverance will bring results