Goodnight, My Someone (Tododeku)

Arranged marriage, newfound feelings, and a bag of coins that started it all.

All his life, Prince Shoto had something different about him, he could sense it. Until one day, while at a potion shop, he discovered what it was. That revelation leads to a world of trouble, secrets open up and spill out, and soon the potion shop owner and the prince find out the true cost of love.