in the scene at the lake when jack and ennis have the big fight, ennis says to jack 'in them early days , i'd just quit the job...but i can't quit this one"
then , in the last scene, when alma jr. asks ennis to be at her wedding, he first declines because of work, but then changes his mind once he sees her disappointment, and makes a comment about skipping work and to hell with the consequences "'cause my daughter is getting married".
ennis also makes a point to ask alma if curt "loves" her, and therefore, places the most importance on that very emotion.
in light of this, it seems to me that this last scene with alma shows the lessons ennis learned from losing jack, and perhaps the lessons of what's really important in life.
ennis was the practical man..working, makin' a living, payin' child support.....etc....
and yet, the 'practicality' which he lived his life by, seems to lose it's importance here. i found this to be where the conclusion of ennis's story is....and maybe that's one of the things he meant when he said "jack i swear"...
any other comments on ennis willing to lose his job due to attending his daughter's wedding, like he used to in the 'earlier days' with jack? i think it's a very important element since he couldn't see jack in august because of his work....
maybe he regretted that, and wasn't going to allow it to interfere in 'missing out' on things anymore, such as alma jr. wedding.