First of all, you can NOT diagnose a battery by messure voltage, that doesnt say **** about how much amps it can hold, you Will have to have a load test done to see if its good.
You can messure the voltage on your battery while engine running to see if alternator works, should read 13.5-14.4V if it fine.
If battery and alternator check out good, its your starter, but you say you can jump it and it starts with no problem., then its not the starter.
So i hold my bet on alt or battery, Get it running and check if alternator works, if so , its def your battery.....
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2004 Grand Cherokee Overland 4.7 HO Quadradrive
95 ZJ Limited 5.2 Winter Project
Sold 94 ZJ Laredo 4.0 Winter Beater
R.I.P. 2000 Grand Cherokee Limited, 4.7 V8, Quadradrive, Shale Green Metallic, Agate/Carbon interior, Well modded and highly missed :(