i haven't read the full chapter yet but i have to say suddenly shifting a political marriage for a lowly poor girl could lead to serious coup d'état if it become official since the girl have strong baking and assuming her family has strong connection if their reputation was pushed like that they would with no doubt plot against the kingdom and even if they lose their damage will be great the country will be left venerable to any invasion in fact they could do contract with another country from outside to weaken their country and share loots that's why their marriage is important to keep balance right
any right minded king would quickly disthrone the prince and give the throne to another one of his plenty reliable sons since leaving the country to such a retard will lead to many damages and proceed to engage her to the new crown prince to calm the nobles
long story short :
it only lead to a very serious Backlash