It's usually seen as a matter of trust. I consider the phrase "I trust you absolutely" not only pretty stupid but incredibly arrogant - you are not only saying

It's usually seen as a matter of trust. I consider the phrase "I trust you absolutely" not only pretty stupid but incredibly arrogant - you are not only saying you trust the other (which is good and reasonable) but you are also saying you could not be mistaken (which is foolish). Trust, but be prepared for being wrong in doing so.