There's a lot about this singer and this song that reminds me of not only fellow singers Akiko Kosaka（小坂明子）and Agnes Chan（アグネス・チャン）, but also of the balladry from 60s singer Connie Francis.
Yuko Sanuki（讃岐裕子）had a brief career between 1975 and 1979 with just 5 singles and a lone album before she retired from show business. Her debut single was "Aru Hareta Hi ni" (On One Fine Day), released in May 1975, and I think right from the start, the most noticeable trait was her high and clear voice. Composed by Masaaki Hirao（平尾昌晃）and written by Michio Yamagami（山上路夫）, this wistful song could have Sanuki looking skywards and wondering aloud whether she will ever find her Prince Charming again. To be honest, I'm kinda surprised that she didn't get any more successful, but I guess that's how the ball bounces.