Ah, I see. I was thinking about the Norwegian sentence in isolation.
Since "vil" is also used to express wants, wishes, and desires, we often fall back on "kommer til å" as the unambiguous alternative for expressing future. Thus it becomes a much more widely used future tense than "is going to", and does not carry the same connotation of near future.
If you google "Jeg kommer aldri til å glemme" and "Jeg vil aldri glemme", you should get about the same amount of hits for both.
Jeg kommer aldri til å glemme deg - it's a very common phrase. I can't say it holds anything else than Jeg vil aldri glemme deg (I will never forget you). My guess is that combined the near future phrase of "going to" with far future "never" is a way of strengthening the expression, if you don't think never ever is good enough. I know you think I'm going to forget you, but that will never happen! I am never going to forget you!!
I can think of several other ways of switching between something that "will never" something, and saying something "never going to" something.. This scar will never fade/Dette arret vil aldri forsvinne. This scar is never going to fade/Dette arret kommer aldri til å forsvinne. I will never do that/Det vil jeg aldri gjøre. I am never going to do that/ Det kommer jeg aldri til å gjøre.
But in constellations on it own, kommer til å is near future. Saying "Dette kommer jeg til" in a lecture, means you will broach the subject shortly (ie I will get to this), often as not omitting saying soon or shortly. Or if you are at the doctor for some flu shot "Dette kommer til å gjøre vondt" - this is going to hurt (real soon).