A person should always be honest.
Act 1, Scene 1
Benvolio speaks to the Prince about the fight that broke out, "I drew to part them, in the instant came the fiery Tybalt with his sword prepared... while we were exchanging thrusts and blows came more and more..." (lines 98-104). Benvolio is honest when the Prince asks him what took place, even noting that he drew his sword at Tybalt. Benvolio could havebeen punished but he chose the route of telling the whole truth and is continued to be a character that is relied on. This also shows an external conflict taking place between Tybalt and Benvolio who are natural enemies because they are from opposing families, Capulet and Montague.
Act 3, Scene 1
Benvolio explains to the prince that "Tybalt here slain, whom Romeo's hand did slay..." when he is asked who killed who in the fight that took place with Mercutio, Romeo, and Tybalt (line 114). Though Romeo was definitely going to be severly punished for killing Tybalt, even though Romeo was trying to give Mercutio, Benvolio and Reomeo's good friend, Benvolio was honest and told the Prince what Romeo did. This shows how reliable Benvolio's character is and relates to the theme because his honesty kept him out of trouble with the Prince and because Benvolio is so well relied on, the Prince trusted that Benvolio was telling the truth about Tybalt killing Mercutio which gave Romeo less punishment.
Act 5, Scene 3
Balthasar tells the Prince why he is at the tomb with Romeo, "I brought my master news of Juliet's death, and then in the post he came from Mantua. To this same place, to this same monument" (lines 287-289). Though Balthasar is seen at a crime scene and is at risk of severe punishment, he still explains the truth of the situation about why he was there and even reveals that he is the reason Romeo found out about the death. This honesty keeps him from getting any punishment, though if he had chosen to keep it a secret or lie he could have been punished for dishonesty.
Act 3, Scene 5
Instead of Juliet telling her parents about her marriage with Romeo, she suspiciously tries to get out of her marriage with Paris with no excuse, "Delay this marriage for a month, a week. Or, if you do not, make the bridal bed in that dim monument where Tybalt lies" (lines 200-202). This relates to the theme due to Juliet's hiding of the truth, she finds herself in a predicament where she is either forced to marry Paris or kills herself, she could have just been honest with her parents. Even though the punishment could be her being disowned by her parents, she would not have needed to kill herself or fake her death and she could have run off to meet Romeo.