The heart-shaped necklace Gumiho Shin Woo Yeo (portrayed by Jang Ki Yong) gave to Lee Dam (portrayed by Hyeri) when he confessed that he loves her is from the luxury Parisian brand FRED.
The necklace is part of their Pretty Woman collection and is made of 18k white gold and diamonds. There are also rose gold variants, and the jewelry comes in different sizes. The said product costs around 2,800 dollars or approximately 140,600 pesos.