"Let it be known that" is a powerful phrase that is often used to express important information or a declaration. However, there are other synonyms that can be used to convey the same message. One option is to say "it should be noted that," which emphasizes the importance of the information being shared. Another alternative is to use "be aware that," which implies that the recipient should take specific action based on the information being provided. Finally, "please be advised that" is a formal variant that is often used in business or legal contexts to ensure that the recipient understands the gravity of the message being delivered.