IPA: /ʌnˈdaʊtɪŋ/
KK: /ʌnˈdaʊtɪŋ/
Having complete confidence and no doubts about something.
She was undoubting in her belief that they would succeed.
Undoubting → It is formed from "un-" (meaning not) and "doubting" (from Old French *doubter*, meaning to hesitate or be uncertain). The word "undoubting" means not hesitating or being certain without doubt.
Think of 'not' ('un-') being added to 'hesitating' ('doubting') — that's why undoubting means being certain without any hesitation.