IPA: /ˈɡaɪləsli/
KK: /ˈɡaɪləsli/
In a way that is honest and free from deceit or trickery.
She spoke guilelessly, sharing her true feelings without any hidden motives.
Guilelessly → It is formed from "guile" (from Old French *guile*, meaning deceit or trickery) and the suffix "-less" (meaning without) and the adverbial suffix "-ly" (meaning in a manner). The word "guilelessly" means in a manner that is without deceit or trickery.
Think of being 'without' ('-less') 'deceit' ('guile') — that's why guilelessly means acting in a way that is free from trickery.