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 subsidiary indication.
'trade fairs' becomes 'expos'.
'lead to' says to take the initial letters.
The first letter of 'enrichment' is 'e'.
(Other definitions for expose that I've seen before include "Lay bare", "Reveal or unmask", "Lay open, reveal", "Unmask or denounce", "Open to view", "Show up", "Disclose", "Bring to light", "Uncover, expose to view" and "Bring into view".)