[bdshaw]

Words have meaning
Here's what many of your contacts really hear

Why does the expression 'to be perfectly honest with you' actually mean?
1. I am just about to lie
2. I usually don't tell the truth but this time I might
3. You are just about to be fired
4. You are about to be wildly overcharged for simple maintenance
feel free to contribute

[Sean Cash]

It definitely can insinuate different things. I had actually just read up on a study recently that showed borrowers who wrote that they "promised" to pay back a loan were more likely to default than people who didn't explicitly promise.

I think "to be perfectly honest" means, don't ask any more questions about my intentions because of the facts that I am about to tell you.

[thudson]

I think it borders more on what you would normally say about an idea/item/etc. When someone offered you a deal that does not particularly sound appealing but you do not want to be confrontational, you might simply say that it sounds great to move on and get out of the conversation. If in the environment where you can speak freely, you then might say "to be perfectly honest, this deal is a horrible idea" and not have to worry about the ramifications of those around you because you know your audience.