Doubt

An emotion experienced when one’s truth judgments (propositions considered to be true) include equal degrees of belief and disbelief. One’s truth judgments is dependent on probability, credibility and plausibility of the propositions.

Reference:
Frijda, N. H. & Mesquita, B. (2000). Beliefs through emotions. In Frijda, N. H., Manstead, A. S., & Bem, S. (Eds.). Emotions and beliefs: How feelings influence thoughts. Cambridge University Press.