The phrase “to be honest” is common in conversation, for emphasis, as an admission, or just a verbal tic.
In business it is an unfortunate phrase. Does it mean that although the speaker often tells lies, on this occasion he is telling the truth? It calls in doubt the very thing that it seeks to assure. It never reassures me, and in business I never use it.
We fondly remember long negotiations in the Middle East with the Dutch lead negotiator for one of our co-venturers, Mr N____.
Mr N____ habitually used the phrase “to be honest”. When he was under pressure or especially keen to be believed it became “to be totally honest”.
At a social event one of the protagonists on the other side told us with hilarity: “We always know when Mr N____ is going to tell us a lie. He starts the sentence with “to be totally honest”!”
In business honesty and trust are central, and vital. The presumption must be that a person is telling the truth, unless there is reason to think otherwise. Business is hardly possible otherwise.