To be suspicious.
To have no confidence in (something or someone).
To be wary, suspicious or doubtful of (something or someone).
To suspect, to imagine or suppose (something) to be the case.
Lack of trust or confidence; distrust, untrust.
the doctrine that this world is the best of all possible worlds
a tendency to expect the best, or at least, a favourable outcome
the belief that good will eventually triumph over evil