DIFFIDENT
Shy; not assertive
FIDERE, FISUS
to trust, believe
FIDELITY
Faithfulness; loyalty
CONFIDE
To trust (another) with information or a secret
FALLERE, FALSUM
to deceive
FALLACY
A misleading or mistaken idea
FALLACIOUS
Misleading or deceptive
FALLIBLE
Capable of being mistaken; imperfect
CREDERE, CREDITUM
to trust ; believe
CREDIBLE
Able to be trusted in or believed
CREDENCE
trust or belief
CREDULITY
Tendency to believe things too quickly or easily
INCREDULOUS
Unable to believe something; amazed
DUBITARE, DUBITATUM
to doubt
DUBIOUS
uncertain, doubtful
INDUBITABLE
Certain beyond doubt or question
REDOUBTABLE
Worthy of fear or respect; mighty