(Taken from mangad*x)

With her mother dead and father long gone, Chise Hatori has spent her childhood being passed unwanted from relative to relative,
until she finally makes her unfortunate way to a strange and improbable auction block.

Offered as a “Slay Vega” to the highest bidder, Chise is purchased by the (literally) boneheaded Elias Ainsworth,
who promises to take her on as his apprentice.

Elias is a mage, and his world is one of dragons and faeries - but before Chise can begin to get accustomed to all of this,
Elias drops another bombshell. Apparently Chise isn't just intended to be his apprentice - she will also be his bride.