adverb Date: 14th century in a sure manner:, without danger or risk of injury or loss ; safely, b. with assurance ; confidently , without doubt ; certainly , indeed , really , see: sure
SURELY
Meaning of SURELY in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012