Collocations for pessimistic - adj.

be, feel, look, prove, seem, sound
These figures look quite pessimistic.

become, grow
remain

extremely, fairly, very, etc.
deeply, terribly
increasingly
overly, unduly, unnecessarily
His predictions proved unduly pessimistic.

generally

about
I am deeply pessimistic about the future.

Pessimistic is used with these nouns:
assessment, estimate, expectation, forecast, mood, outlook, scenario, view