RYUU TO RYUU NO KEKKON

Ryuu to Ryuu no Kekkon summary:

After a long war, Licorice, a princess of the Wyvern Kingdom, and Leifa, a princess of the Dragon Kingdom, are to be married as a sign of peace. Former enemies, the two begin a new life together…
Licorice has complicated feelings about the political marriage, but she can't help becoming attracted to Leifua, who seems so lonely, despite her outward indifference.
Two girls who do not know how to love, bond with each other as they heal each other's broken hearts.
(Source: Shiori-on, translated)