"He had never felt this for anyone."
Translation:Él jamás había sentido esto por nadie.
Is there a reason you don't need the pronoun (me, te, le se, etc.) here? Isn't sentarse reflexive?
Why jamás instead of nunca? still unclear on this, thought i knew but not now after this sentence.
I believe "nunca" is accepted as a possible translation.
Also, jamaud is also correct in the difference between "jamás" and "nunca".
Yes, there is a reason. cualquiera is not used in negative sentence in general (unless very specific examples), because Spanish is a double negative language. Basically we say He had never felt this for nobody in Spanish