あいまいに (translations)→ doubtfully indistinct inscrutable non-committally noncommittally tentatively unconvincingly vaguely
うっかり (translations)→ absentmindedly accident accidentally careless carelessly fear heedlessly inadvertent inadvertently injudiciously let nearly thoughtlessly unguardedly unintentional unthinkingly venture
おぼつかない (translations)→ hesitant inarticulate lousy undercurrent uneven unevenness unsteady
ためらいがちに (translations)→ awkwardly hesitantly self-consciously
自信なげに (translations)→ feebly timidly
弱々しい (translations)→ feckless flaccid fragile gentle sickly thinly thready weak