Princess Alexandra of Hanover
Princess Alexandra of Hanover was the only child of Princess Caroline of Monaco and Prince Ernst August and was a pretender to the throne of the defunct Kingdom of Hanover. Even though Princess Alexandra had half-siblings from her mother and father because of their previous marriages, she was the only one who had any title and style. The princess was the tenth in line for the succession of the Monegasque throne. Princess Alexandra of Hanover was not yet betrothed but had been in a relationship with Ben-Sylvester Strautmann since 2016.
Prince Constantine-Alexios of Greece and Denmark
Prince Constantine-Alexios of Greece and Denmark was the son of the Crown Prince of Greece, Pavlos, and the Crown Princess of Greece, Marie-Chantal. Prince Constantine-Alexios, more commonly known as Tino, was the godson of Prince William. The prince was studying at Georgetown University in Washington, DC, and was one of the youngest royals in our list. Prince Constantine-Alexios managed to have a solid fan base using his social media accounts. Yet, there was no indication that the 19-year-old prince was involved in a relationship with anyone.