The Saint's Magic Power is Omnipotent (Light Novel) Vol. 9

Sei's first journey abroad in this other world is to Zaidera and she's trying her hand at making magical amulets. She's also over the moon about her engagement to Albert. While busy with wedding preparations, Sei overhears how one of the members of First Prince Kyle's delegation to Zaidera is now bedridden with an unknown illness. Naturally, Sei can't just stand idly by, and, with that, her trip to Zaidera is hurriedly assured. However, upon her arrival, Kyle informs Sei that no one is sick and to make matters worse, the port has been closed, so they're now stuck abroad.