This marriage alliance with the Elizabeth family would only end up benefiting the Luther family in the long run.
Therefore, she accepted the situation with a heavy heart and decided not to foil the wedding completely. She put all the weird and destructive thoughts that kept popping up in her head aside and focused on her family's progress instead which allowed her to distract herself.
On the contrary, Luna who had been the first to know about this development was completely unaffected. Even though she should have been the most affected by the situation because she had been Zach's first woman, Luna supported Zach unconditionally. Just that little bit of reassurance from Zach earlier had been enough for her to set all her worries aside.