"I think that his "Jack, I swear" nebulously represents the huge jumble of feelings -- love, grief, regret, affection, sorrow, loneliness, devotion, despair, etc. -- that constantly threaten to overwhelm him at this point."
latjoreme
Yes, I think this gets at Ennis, how he is inside himself, often nearly overhelmed by emotions that he doesn't always understand and sometimes cannot control and which he often fears giving into. The "jumble of feelings" at the moment of "Jack, I swear..." is a good possible explanation for why he can't complete the sentence. We all know Ennis loves Jack, more than anyone in his life and will never forget him, but here, in what latjoreme says, is what I think, a real in-sight into Ennis's heart and mind. All of what everyone has imagined the line means only adds to our understanding, but this is really the heart of the matter, for me anyway. Thanks, latjoreme! And thanks to all who are contributing here to what is, though I didn't know it would be, a hot topic!
Cheers...
Rayn