I can somewhat understand the MC's motivation for lying- ... Wait, no. I can't begin to defend his actions, Luna is another story. Since gods exist and sometimes grants blessings to their favorites, the upper aristocracy place greater value on poise
and human arrogance, perhaps to delude themselves into believing they're above the gods. So Luna might've nearly took her life because she refused to live on as a 'filthy noble,' and those sentiments were only intensified by her environment.