A constant offset stays the same
If the same sound is early by about the same amount near both the beginning and the end, you are probably dealing with a fixed offset. Moving the audio may be enough.
Check more than one moment. A single word is not a reliable way to decide what is happening across an entire recording.
Steady drift changes with time
If the audio is close to correct at the start but increasingly early or late near the end, a simple shift will only fix one part of the recording. The audio timing also needs a small stretch or compression.
SyncMend uses two manually selected points to estimate a linear correction. That model assumes the timing changes steadily between the points.
Use the distance between the points
For example, if the audio is 0.1 seconds early at minute 2 and 0.9 seconds late at minute 58, the measured change is one second across 56 minutes, not 60 minutes.
The interval between calibration points matters. It is not necessarily the full video duration. SyncMend also accounts for the fixed offset before it processes the audio.
Know when the model does not fit
A sudden jump, an edit that changes timing, or several unrelated drift segments cannot reliably be repaired with one linear correction. If both ends look correct but the middle does not, stop and investigate instead of exporting repeatedly.