Middle English from Middle French from Latin: confidentia; "firmly trusting, bold", confidere "to have full trust or reliance"; from com- + fidere "to trust" (faith)
Trust - noun. Middle English: from Old Norse: traust "help, confidence"; Proto-Germanic/Old Frisian/Dutch: traust/trost/troost "comfort, consolation". Gothic: trausti, "agreement, alliance"; Old English: treowian "to believe, trust", treowe "faithful, trusty, true". Verb - Middle English: trusten from Old Norse: treysta from traust, "to trust"
Faith - noun. Middle English: feith from Anglo-French: fed; Old French: feid, feit "faith, belief, trust, confidence, pledgefrom"; Latin: fidem, fidēs "trust, faith, confidence, reliance, credence, belief"
As you can see, confidence ties back to trust and trust ties back to faith. All three words are undoubtedly bound together. Having faith is having confidence and trust in the divine spirit within you. Spirit provides the life you need to breathe out here on a daily basis, so why not have faith and abide by the laws set forth to keep order and ensure that all life make be able to continue on their pursuit of happiness. When we smile, we are exhibiting the full life of our own unique fingerprint/spirit given to us by The Most Highs. If confidence is faith, faith secures life, if life is love, true love is faith. If faith is love and love is light, faith is light as well. Now you can connect why religious/spiritual figures in paintings are shown with halos/glow around their heads. That is a symbolic and literal depiction of the divine love/spirit they possessed within. Holiness/wholeness produces light like the Sun. Quite frankly, only a fool would choose to go against the essence of who created all creation. Let confidence/trust/faith in yourself/divine essence within give you life.