One who insists on facts is later confused (7)
I believe the answer is:
realist
'one who insists on facts' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'is later confused' is the wordplay.
'confused' is an anagram indicator.
'is'+'later'='islater'
'islater' with letters rearranged gives 'REALIST'.
Can you help me to learn more?
(Other definitions for realist that I've seen before include "no Walter Mitty?" , "One's practically inclined" , "Sensible man" , "Pragmatic type" , "One without illusions" .)