believing

/B IH0 L IY1 V IH0 NG/
verb
  1. 1

    To accept as true, particularly without absolute certainty (i.e., as opposed to knowing)

    โ€œI believe there are faeries.โ€

  2. 2

    To accept that someone is telling the truth.

    โ€œWhy did I ever believe you?โ€

  3. 3

    To have religious faith; to believe in a greater truth.

    โ€œAfter that night in the church, I believed.โ€

  4. 4

    To opine, think, reckon

Antonyms

noun
  1. 1

    The act or process of having faith, trust, or confidence in.

  2. 2

    Belief.

Source: https://en.wiktionary.org/wiki/believe, https://en.wiktionary.org/wiki/believing