Trade fairs lead to enrichment, a revelation (6)
I believe the answer is:
Here is my best explanation:
'a revelation' is the definition.
(expose is a kind of revelation)
'trade fairs lead to enrichment' is the wordplay.
'trade fairs' becomes 'expos'.
'lead to' indicates taking the first letters.
The initial letter of 'enrichment' is 'e'.
(Other definitions for expose that I've seen before include "Lay bare", "brings out crime", "Show up", "outing", "Reveal, uncover", "show up", "Make visible or obvious", "Lay out to view", "Open to view" and "Uncover or unmask".)