Certainly

その通り

sono tōri

(emphatic affirmative answer)

もちろん

mochiron

(emphatic affirmative answer)

全く

mattaku

(emphatic affirmative answer)

必ず

kanarazu

(without doubt, surely)

必ず

kanarazu

(emphatic affirmative answer)

確かに

tashika ni

(without doubt, surely)

確実に

kakujitsu ni

(without doubt, surely)

絶対に

zettai ni

(without doubt, surely)