To finish the stronger belt hand sew, machine sew or use a contact cement on both sides to attach the grosgrain / petersham tap to back of belt.
If using contact cement you apply to both sides and wait at least 15mins until not gloopy or sticky then press firmly together. weight down if you want. it will be at full strength after 24 hours.
This is a strong tape and you can punch holes for inserting metal eyelets for the holes if desired..
Don´t be snobby about gluing textiles! many older books from 1800´s to late 1950´s use glue for fabric belts, handbags, hats and adornments.
Attach buckle to the flat end, punching hole in needed for the spoke.