Apparently, Nintendo themselves who have "no comment" on Bowsette when interviewed by Japanese website J-Cast News, invented her long before the Internet did. U Deluxe which allowed Toadette to transform into Peachette. Based on this information, it's safe to say that Bowsette won't be made official any time soon. The fan-created Bowser transformation, inspired by the Super Crown item in New Super Mario Bros. U Deluxe-which is a Nintendo Switch port of Super Mario Bros.
Upon discovering the description, gamers and artists were left somewhat disappointed, especially those who contributed a wealth of Bowsette fan art over the last few months that helped propel the character to social media stardom.
Sadly, the item has been restricted to Toadette, though Nintendo could potentially revisit the idea in future titles.
Nintendo has confirmed the Super Crown does not work on any other Nintendo character - only female Toads. The possibilities really would be endless.
In our heart of hearts, we all knew Nintendo would never officially acknowledge Bowsette as part of Super Mario canon. It became the new Rule 34 for basically anything to ever exist, leading to some hilarious interpretations and jokes about the Super Mario Bros. series item. U (from the Wii U) with New Super Luigi U thrown in as an added extra-will release on January 11th 2019.
So, there you have it, Nintendo's insistence that "only Toadette can use this item!" seems to be created to shoot down fans hopes of seeing Bowsette.