Here are some related words that I looked up. Not sure which ones are in current usage and which would be considered archaic...
Степень уверенности (Degree of Certainty):

наверно - probably, certainly

вероятно - probably, very likely

несомненно - doubtlessly, without doubt

наверняка - certainly, for sure

возможно - perhaps, possibly

предположительно - supposedly

по-видимому - apparently, seemingly

точно - exactly

безусловно - certainly, undoubtedly, absolutely

определённо - definitely

уверенность - confidence, certainty