I Swapped Fiancés with My Sister Now I'm All In for the Coldhearted Marquess!

The calm and composed noble lady, Sverine.At a ball her business-minded father attended to find a fianc for her younger sister,Sverine experiences a fateful encounter. The Marquess of the Frontier, Nazaire.Supple muscles, a sharp and handsome face, and a ruggedly masculine build.He's her super miracle ultimate type!!!However... he's actually a candidate to marry her sister.Disheartened, Sverine resigns herselfuntil her sister unexpectedly refuses the match.It turns out the sister has feelings for Sverine's own nominal fianc."Then why don't we just swap fiancs!?"Now aiming to reach the altar with her dream man ?The (supposedly) cool noble lady's grand proposal strategy begins!!