However, the one who is to receive the chocolate can absolutely not decline it.

How come?

How come?

Because those are the rules

...and the one who has received chocolate on the 14th of February

...and the one who has received chocolate on the 14th of February

Ohh!?

...has to conduct a ritual known as "Three-fold return" on the 14th of March, on White Day,

...has to conduct a ritual known as "Three-fold return" on the 14th of March, on White Day,

or else they'll be cursed.