I know we must have one or two stories of Super Mario's Peach and Bowser but I was thinking of a story from Bowser's side where he tries to win her over. It would include confessing, forcing himself on her or even transforming her into a female version of himself.
There are many lovely analyses of the Peach-Bowser-Mario triangle. Ive heard from more than one source that it's basically a big RP session between them. Regardless, go for it. Peach is a hot girl - perhaps a more classic damsel than any Disney princess.
Ok, let me explain something about Bowser × Peach - Mario Bowser and Peach are GODS. Peach is WAY higher ranked than Bowser. Mario and Luigi are two dumbass Italian plumbers that got themselves stuck in an alternate reality where they became what amounts to shrine maidens for the local over deity enacting a very hazardous ritual play to keep her four spirit energies in balance in exchange for Quasi-immortality. Bowser can come back from the dead, he's a dragon turtle Kame, and he only kidnaps Peach because if he doesn't she'll kick his ass. The one time he breaks script and kidnaps Mario and Luigi instead she wrecks him with BS Over-Kame magic, and he's NEVER TRIED THAT AGAIN! Daisy, by contrast, is a sorceress queen, and she's cool and all, but there's a reason that she and Luigi are an item instead of Peach's main man Mario 'Jump-Man' Mario: to whit, Peach would shank a bitch. (Or maybe just trash her with divine power, doesn't make much difference.) Bowser raping Peach? OMG, that's so stupid it's funny! Peach likes getting kidnapped and rescued, but he steps one toe out of line and he's gonna get "Hadoken!"-ed into a world of pain! For a more through and detailed explanation see this video:
My pet theory? Peach is Batman. Bowser is Alfred. Mario is an unwitting cover story. “Ma’am, evil is afoot.” “So I see. Deploy the obstacle course, collect the volunteers and the drones, and ‘kidnap’ me.” “What if he gets too close, this time?” Peach smiled, just a touch. “How could he? His princess is in another castle.” She considered. “But if he’s good, we’ll bake him a cake.” “We, ma’am?” “Obviously I mean you, Bowser.”
"Bowser, tonight that plumber, his brother and all their friends and racing in a tournament... don't you think that's somewhat suspicious?" "Not really, I mean they do all kinds of crazy stuf…" "No, it is suspicious, I'm sure of it. I think I ought to go down there and check it out, perhaps enter in the race myself..." "Er, just yourself ma'am? Could be dangerous... I hear they're using explosives and Koopa shells... shouldn't you go with someone? … asking for a friend..." "No, don't let your friends know, just come with me! I know your experience backing the Peachmobile into the Peachcave will come in handy." "Very well." "On second thought, he does have a lot of friends... Better check with Wario and that Dry Bones character. But not Waluigi. I don't trust him, ever since he wanted to Smash, but Nintendo wouldn't let him."
If no one else does, I think I might... (Without rape and more seduction though... It also would probably involve Bowser making his own version of the super-crown that creates half-turtle women out of whoever puts it on...)