So basically, after Tia's poisoning, it was deemed that she could potentially be infertile and therefore unsuitable to become empress. She has even lost the support of her own faction and she felt really betrayed but despite this she agreed with them and tried to break off the engagement, again.
So basically, after Tia's poisoning, it was deemed that she could potentially be infertile and therefore unsuitable to become empress. She has even lost the support of her own faction and she felt really betrayed but despite this she agreed with them and tried to break off the engagement, again.