From Longman Dictionary of Contemporary EnglishI must admit/say/confessI must admit/say/confessspoken used to emphasize what you are saying I must say, it gave me quite a shock. → must
Examples from the Corpus
I must admit/say/confess• Lovely site for it, I must say.• They were very polite, I must confess....• This procedure is, I must admit, a limited one, and it is vulnerable to criticism.• He went very red in the face. I must say he never did it again.• But I must say I was deeply disappointed.• Some one must have brought it here for a purpose, but I must admit it looks abandoned.• But I must say she's not always as fractious as she appears now.• At this point I must say that I haven't yet found a carp that didn't eat Tropicanas. 