The first timeline,
"Tomorrow, the duke will make you the duchess, right?? I'm happy for you." Victor took her right hand and kissed it as Marinette stared at him with a worried look.
"I kinda get the ominous feeling..." he raised his head and stared at her with his puppy eyes telling her everything will be alright because he was there.
But will it...?
The next day, the duke died.
The duchy was in chaos, everyone finally revealed their true color. The maid she trusted the most led the imperial army to Marinette's room accusing her of poisoning when seeing the poison in her room.
"It...wasn't me...I didn't--"
And the army was led by a man who was none other than Victor himself, who let Diana in his arm comforting her.
Without finishing her speech, the hand which held hers yesterday slapped her. The pain didn't compare one bit to her heart which started turning to ice.