Transparency
It baffles me how many people prefer to choose obscurity and ambiguity when communicating. What is this fear which they have of being open, honest and transparent? Are they afraid of upsetting the person whom they are speaking to?
In my experience, being transparent from the outset has always led to stronger relationships and more effective outcomes. In an instance where I cannot fully reveal information, I am honest about that fact.
"Unfortunately I can't yet tell you this, but here is why I can't tell you."
It is expected to feel an initial jolt or moment of friction when communicating such a thing, but the long-term effect negates the short-term one. Someone may appear upset that they aren't being told information (nobody likes being kept in the dark) but they will ultimately respect you for telling you this rather than not telling you anything at all.
From a business perspective, look at Monzo. They flipped an entire industry on its head and fostered a new age of banking transparency. They are not without fault or without secrets, but they are better than the incumbents.
The human mind is a fine thing and it certainly likes to wander. Through being transparent, you can put those minds at ease and foster an increase in trust which, both personally and professionally, can only ever serve you well in the long-term.
Apertum honestum est.