Viking no Hanayometachi

In the Viking Brides series:

1-Byakuya no Princess (The Reluctant Princess)
Elli has no memories of her homeland or father, having been raised abroad by her mother with her sisters. When a mysterious man breaks into her house, she finds out that she’s royalty of the far-off land of Gullandria, and that her father is the king! With a reunion in the cards, will Gullandria prove to be all Elli hopes, or will she escape into the arms of the man who brought her there?

2-Gekka no Ayamachi (Prince and Future...Dad?)
Princess Liv Thorson honestly believed she could skulk back to America, her uncharacteristic night of passion a secret known only to a sympathetic sister...and the Viking prince who possessed her underlisse. Then came the baby trifecta--woozy tummy, fainting spell, rash--telltale signs that she and Finn Danelaw had made a lot more than love....
Finn Danelaw was used to hearing all kinds of utterances from women, but "no" wasn't usually among them. He had, however, a proposal for beautiful Princess Liv...and though he'd planned a seduction along with it, he'd learned a long time ago that all good things come to those who wait. For the test results, that is. The pregnancy test...

3-Shukumei no Deai (The Marriage Medallion)
He’s going to be my husband? Princess Brit is forced to marry to preserve the royal bloodline, so she flees the palace and heads for the distant North Sea. But on the way there, her plane crashes, and she is thrown against the steep cliffs. She’s hurt and terrified! As if in answer to her pleas for help, a dark shadow appears. Is he the legendary black knight? No—it’s Eric Greyfell. He’s as beautiful as a hero from Norse myth, but his heart is as impenetrable as a stone statue. And he’s the man she was expected to marry!

4-Kamen no Prince (The Man Behind the Mask)
Dulcie has arrived at a foreign palace to celebrate the wedding of her best friend, the princess of a small country. There, she meets Prince Valbrand, a man with a scar on his face. A hideous burn scar, marring the face of a beautiful man. What cruel fate must he have endured? On the night of the ball, spurred by curiosity, Dulcie dances with him and realizes that she has fallen in love.But as Dulcie grapples with her emotions, a tragedy awaits.