candidly, honestly, truthfully, straight out, to be frank, unfrankly, open-heartedly, simply, bluntly, ingenuously, more...

covertly, evasively, indirectly, obscurely, deceitfully

honestly, bluntly, candidly, directly, more...

to be honest,   truth be told,   i must admit,   honestly speaking,   let’s face it,   to put it plainly,   let's be honest,   to put it bluntly,   i'll be honest,   speaking openly