When you jump your truck, you are placing the clips on the cables, NOT the battery terminals.
Therefore, the first thing to check is for clean battery terminals and cable connectors.
Then, measure the voltage at the battery terminals, not on the cable. Fully charged should be at least 12.6V.
If it is in the 12.0 or lower range it is discharged.
Once it is running, again measure the voltage. It should be between 13.6 and 14.6 for a standard flooded battery.
Otherwise, it isn't being charged.
If all that checks out, then start looking for the parasite that is draining the battery.