Actually no, beliefs do not have to be derived from emotions contrary to popular misunderstanding, (Jung's) "feelings" are detached from emotions or sentiment being instead, a rational impartial perspective of the world.
Emotions are a separate irrational and personal aspect of decision-making that are "involved" and influenced by sentiment. A couple of socionists and MBTI chose to interpret impersonal and personal decision making as the difference between "thinking" and "feeling" but Jung doesn't talk about that at all rather vehemently arguing the contrary.
Socionics is a derivative system with its own perspectives influenced with observations that align with reality as opposed to Jung's esoteric system. The logic of socionics follows it's own axiom so if you are ever to merge the two with MBTI then whatever you are calling socionics isn't socionics. In before real vs fake Socionics/socionists, that's another can of worms people in the east have failed to fix the past 30 years due to a flawed premise - the failure to employ scientific methods.
I spoke to this ESFJ girl a couple of years ago about the idea which seemed stupid to me, but it turns out she was a thinker yet her thinking naturally can be explained by the overlap negating the emotional interpretation of the world.
http://personalitycafe.com/esfj-arti...-function.html