You don't specify, but I assume you are asking about the dialogue between Macbeth and the First Murderer, in Act 4.3 of Shakespeare's Macbeth.
Macbeth tells the First Murderer that he has blood on his face, and the First Murderer replies that it must be Banquo's. Macbeth then says:
'Tis better thee without than he within [better splattered on you than flowing in him].
Is he dispatched? (Act 3.4.14-15)
Dispatched is the euphemism. A line or two later Macbeth uses "did the like" as a euphemism for killing Fleance like the First Murderer did to Banquo.
Those are the two euphemisms Macbeth uses, but I'm afraid the answer to your question is: nothing would happen. The conversation is an aside. No one on stage hears it.
Thus, nothing would happen if he chose not to be cryptic (secretive) and chose instead to be blunt. Since no one else hears him, anyway, nothing in the play would change.