unerring
adj
not making mistakes or failing or missing the mark; consistently accurate 不犯错误的; 万无一失的; 一贯准确的
his unerring taste in clothes, instinct for a bargain, sense of direction 他那万无一失的衣物审美观点、 讨价还价的本能、 方向感
He has an unerring knack of saying the wrong thing. 他有个出言必失的本事.
His aim was unerring. 他百发百中.