What?! "You always will be a good friend" is wrong?
I am complaining to the management!
After two years is still not accepted! I will report again!
O advérbio de frequência se coloca entre o verbo auxiliar e o verbo principal. O DL está certo.
You will always be a good friend.
The position of "always" there sounds a little awkward in English.
is this the correct form of the future tense, or is it more colloquial?
In English, it is likely that people would use "will" rather than "going to" since the statement seems to involve an opinion. "Will" is more subjective than "going to".
[I know that] you will always be a good friend.
It's also right, but it is more common to say "vai ser".