Natyashastra
त्रासश्चैव वितर्कश्च विज्ञेया व्यभिचारिणः । त्रयस्त्रिंशदमी भावाः समाख्यातास्तु नामतः ॥ २१॥
Fear, doubt, and delusion are also considered psychological states. These thirty-three states are known by name.
english translation
trAsazcaiva vitarkazca vijJeyA vyabhicAriNaH । trayastriMzadamI bhAvAH samAkhyAtAstu nAmataH ॥ 21॥
hk transliteration by Sanscript