How to have a NPC check the friendship/happiness of your Pokemon?

[Cardboard Slime]

I'm doing a NPC event where she checks your PKMN friendship. If your PKMN reaches a certain value, she will give you a reward.
! couldn't find any scripts so far that does this. Any solutions or scripts/coding I need to do to do this.

 

[Vendily]

In the default Essential's maps, in Daisy's House (map ID 8), the leftmost event checks for the happiness of the selected pokemon and gives a ribbon if it's maxed out.

All the NPCs in that map, except for Daisy, check for properties on the pokemon and have differing text and rewards.