Komuro added that he was thankful and happy to have been accepted by her parents, Prince Akishino and Princess Kiko, and her grandparents, Emperor Akihito and Empress Michiko.
The couple seems to have a loving relationship as they both revealed their feelings during the press conference.
Japanese Emperor Akihito's oldest granddaughter, Princess Mako, will soon become a commoner following her decision to marry a former classmate with no blood connection to the island nation's royal family.
But the celebratory mood was soured by North Korea's sixth nuclear test the same day, with Imperial Household Agency officials and the couple's acquaintances expressing displeasure that the detonation coincided with the auspicious occasion.
When Princess Mako marries Kei Komuro, she is expected to keep her job as a researcher at a museum at the University of Tokyo, which she landed after completing a master's degree in art museum and gallery studies.
Princess Mako (right) is engaged to Kei Komuro (left). She and Komuro reportedly exchanged emails and had phone conversations before she came back to Japan in September 2015. But due to the unfortunate torrential rain that flooded northern Kyushu that month, the royal family chose to postpone the announcement.
Their engagement will become official in Imperial terms after Komuro's messenger visited the princess' Imperial residence with gifts.
The couple seldom used cars when they went out together, mainly travelling by train like other young people. One among the rituals will be the Kokki no Gi.
Princess Mako is expected to Wednesday next year. However, for many, this isn't good news, as the Princess is said to marry a commoner.
Princess Mako's 83-year-old grandfather, Emperor Akihito, is expected to abdicate next year - Japan's first abdication in two centuries.
Reports also suggest that the emperor might attend the wedding. The Imperial family will witness the first wedding since 2014.
At a press conference held at the Akasaka Imperial estate in Tokyo's Minato Ward on Sunday afternoon, Princess Mako and Komuro spoke about how their romance started and how they feel now.
Mako's renouncement of royal status will make her the 8th member of the Imperial family to renounce status in order to marry since World War II.