Responses
The 2nd prince overworked her deliberately because she is a commoner, to the point her magic organ got heavily damaged, the moment it is completely broken, she can no longer user her power. So now he wants to get rid of the useless saintess and spite the frontier by sending them a useless and commoner saint.
But MC still uses her power, because she feels obliged to be somehow useful until the moment she completely breaks.
Just as you mentioned the story of a too good to be true saintess, which is abused by everyone around her for no good reason.
The pacing is too fast & it’s your typical cliché story with a commoner saintess that face nothing but harshness, her family doesn’t care about her and she gets bullied for her origins at her workplace. I didn’t understand why the 2nd prince summoned her to order her to marry the marquess (ML), like it was out of nowhere.
Oh and the ML tells her there won’t be any love in their marriage before proceeding to kinda fall for her 2 chapters later.
To summarise, it’s not worth the reading