@tomlegamer Not being familiar with your fridge I can't be certain, but usually the key determinant for me is that it becomes completely silent for an extended period of time.
Samsung fridges often have separate fridge and freezer evaporators which confounds things, but if you hear any mechanical noise at all, say from a fan, it can't be defrosting. Any airflow through the evap would heat up your food and also slow the defrost.