I looked for it, but couldnt find how one could interpret feelings represented by the 4 of swords.
Is it a feeling of calm, safe? Or indifference, resting with no regard/awareness of the other preson?
Yes!
Okay ... sorry, that's just what I first thought as I read your post.
But along with what you've put here and what others have added, I would say that this could also be about ignoring a problem, hoping it will "just go away". There is also an aspect (to me) of ... oh, I wanted to say "turning your back" on something or someone, but that's not really it. These would be a couple of more "negative" aspects of the "repose/rest" theme. There are feelings of "loneliness", withdrawal from others and so forth here too. Then again, one may be having a chance to take a break from conflict here, a chance to rest before returning to the argument for example.
Also, because of the "thinking" aspects of swords, I've often thought of "writer's block" when I see this card.
Hope this helps.