настойчив|ость - ж. perseverance, persistence
~ый
1. (о человеке) persevering, persistent, dogged
2. (выражающий настойчивость) insistent
~ые просьбы insistent/pressing requests
Большой русско-английский словарь
НАСТОЙЧИВОСТЬ
жен. recalcitrancy, persistency, insistency, contrariness, contumacy, insistence, obduracy, obstinacy, patience, perseverance, persistence, pertinacity, perversity, recalcitrance, refractoriness, stubbornness, urgency, rebelliousness, rebelliousness, rebelliousness, steadfastness, unyieldingness