IPA: /ˌʌn.səˈspɪʃ.əs/
KK: /ʌnˈsʌspɪʃəs/
Not having doubts or suspicions about someone or something; trusting or believing without question.
She had an unsuspicious nature, always trusting others easily.
Unsuspicious → It is formed from the prefix 'un-' (meaning not) and the root 'suspicious' (from Latin 'suspiciosus', meaning inclined to suspect). The word 'unsuspicious' means not inclined to suspect or distrust others.
Think of 'not' ('un-') being added to 'suspicious', which means someone who does not suspect or distrust others.