Don't believe me, but believe these links :)
https://hero.fandom.com/wiki/Princess_Cadance
https://mlp.fandom.com/wiki/Princess_Cadance
https://www.amazon.com/My-Little-Pony-Princess-Collection/dp/0316389307
At some point I also thought her name was written Cadence, but when I started to collect the singing princess toys and had to look for them on eBay, I realised that damn, it's Cadance, not Cadence!