Persuade Greek character: talk up trinkets (10)

'trinkets' is the definition.

'persuade greek character talk up' is the wordplay.
'persuade' becomes 'sell' (selling is a kind of persuading).
'greek character' becomes 'eta' (letter from the Greek alphabet).
'talk' becomes 'gab' (I've seen this in another clue).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'sell'+'eta'+'gab'='selletagab'
'selletagab' written backwards gives 'BAGATELLES'.