Performance basics
Why does perfume fade quickly on me
A quick-fading impression can involve the fragrance's development, application, conditions and your perception. Before assigning one cause, distinguish the loss of a bright opening from the absence of every later scent.
A HUME Fragrance buying guide

Identify what changed
Write whether the opening became quieter, the surrounding presence reduced or no close-range impression remained. Those are different observations.
Check the actual application
Note the product and dispenser and follow its directions. A different atomizer or a partial application can complicate a comparison with another wear.
Repeat without improvisation
Try the same candidate in similar ordinary conditions before changing several things at once. Avoid heating, diluting or otherwise altering the product to chase a claim.
Try this before you buy
Describe exactly what you mean by fading and record that same observation during another appropriate trial.