Synonyms of 'certainly'

absolutely, actually, all right, alright, Amen, assuredly, aye, clearly, decidedly, decisively, definitely, distinctly, exactly, factually, fatefully, fine, forsooth, good, hear, historically, indeed, ja, naturally, necessarily, okay, oui, patently, positively, precisely, quite, rather, really, right, righto, Roger, seriously, sure, surely, sure thing, truly, undoubtedly, verily, yea, yeah, yep, yes