Use statements that also ring true. – “We have faith in a promised benefit only as long as there is nothing in our experience to dispute or contradict it.”
Credibility for all the claims made is increased when relatively minor faults are admitted. – “… the easiest way to make a person believe what you are going to tell him is first to tell him something that he already knows is true.”
Make your facts more specific to make them more convincing. Exact values instead of “almost”, “close to”
Use actual photographs, rather than drawings.
Answer to more “why’s”. Believability increases if copy is clear, reasonable and logical. This helps to answer why the promise can be performed.