Helmar Fabric Glue as my son loves his Undertale wallet and wants to be able to keep using it and repairing things to reduce what goes to the tip is really important for the planet.
Helmar Fabric Glue along the fabric that has to adhere under the zip section.
I then held the 2 pieces together until the glue felt touch dry.
I then stood the wallet up with the coin part open and let it dry longer to ensure a strong hold.
My son is so happy that he can keep using his wallet.