I think that the mantra-like effect of the last two lines plus the mention of unfulfilled promises suggests a certain “call of the void” from the wintery scene. So I think there’s a lurking darkness to the poem behind the surface story of entrancing natural beauty on the way to some engagement. (But I’m not sure if that was Frost’s actual intent.)
Yes that’s the read I got as well. He is contemplating letting himself get taken away by lingering too long in the frigid conditions, but then snaps out of it.
