/ˌoʊvərˈsel/
over·sell
BrE /ˌəʊvəˈsel/
NAmE /ˌoʊvərˈsel/
[often passive]
~ sb/sth/yourself
to say that sb/sth is better than they really are
He has a tendency to oversell himself.
~ sth
(business)
to sell too much or more of sth than is available
The seats on the plane were oversold.