Which word -- vital or essential?

These words have the same meaning but there can be a slight difference in tone. 𝙀𝙨𝙨𝙚𝙣𝙩𝙞𝙖𝙡 is used to state a fact or opinion with authority. 𝙑𝙞𝙩𝙖𝙡 is often used when there is some anxiety felt about something, or need to persuade somebody to show that a fact or opinion is true, right or important. 𝙑𝙞𝙩𝙖𝙡 is less often used in negative statements. 

◆ It was vital to show that he was not afraid. (√)

◆ Money is not vital to happiness. (×)

𝐒𝐨𝐮𝐫𝐜𝐞: Oxford Advanced Learner's Dictionary