こっそり の訳語→ creep discreetly furtively quietly sott-voce stealthily surreptitiously unperceived unseen
ひそかに の訳語→ mentally private secretly silently softly unadvertised
ひとりで の訳語→ alone full-time helpless oneself single-handed unilaterally
個人的に の訳語→ personal personally
内緒で の訳語→ semi-privately
内心 の訳語→ actually conscience enjoy enormously inside internal inward inwardly secret sneaking truth within
