Here, "deliberate" is a verb, pronounced /dɪˈlɪb.ə.reɪt/ with the main stress on the second syllable and a secondary stress on the fourth syllable (unlike the adjective: /dɪˈlɪb.ər.ət/).
From the Cambridge Dictionary:
to think or talk seriously and carefully about something:
The jury took five days to deliberate on the case.
The committee has deliberated the question at great length.
[ + question word ] He's deliberating whether or not to accept the new job that he's been offered.