razočaravati

1. to disappoint
   Ova ekipa nas stalno razočarava. — This team keeps disappointing us.
   Ne želim da razočaravam roditelje. — I don't want to disappoint my parents.
2. (razočaravati se u + acc.) to become disappointed; to lose faith
   Sve se više razočaravam u ljude. — I'm becoming more and more disappointed in people.

"To be disappointed in" is razočaravati se u + acc. (u ljude, u politiku).