Hi there! Well Elliot, here it is!
RING-Donate at least 5000 points in 3 donations or more and check No. 15 in souvenirs
CAPE-Donate at least 12000 points in three donations or more and see No.16 in souvenirs
CROWN-Donate at least 30000 points in 3 donations or more and see No.17 in souvenirs
Three cheers for his Majesty The King Of Tamagotchi Connection! Hip hip Hooray!
Jai
PS:Check your items and you will see the royal costume