Though I know that RAW states that Vicious Mockery is initiated through a "string of insults", my question is about what would happen if you used it elsewhere than a tavern brawl or the like.
As a reference, the cantrip Vicious Mockery is written as:
You unleash a string of insults laced with subtle enchantments at a creature you can see within range. If the target can hear you (though it need not understand you), it must succeed on a Wisdom saving throw or take 1d4 psychic damage and have disadvantage on the next attack roll it makes before the end of its next turn.
This spell's damage increases by 1d4 when you reach 5th level (2d4), 11th level (3d4), and 17th level (4d4).
Unlike similar opinion-effecting spells like Friends and Charm Person, the wording of this spell doesn't finish with a caveat "when the spell ends, they will know you influenced them and it will piss them off", revealing that, it's the insults and not the subtle enchantments that will upset them.
Given this, my understanding of how the cantrip works is that you insult someone, using magical enchantments to boost the persuasiveness of your words. If they fail a wisdom saving throw, they take your words to heart, shading their next move with a veil of sadness, doubt, or fear clouding their judgment. As your words sting, they take minute psychic damage.
If that's the case then, I'm curious to know what would happen if your character tried lacing the same subtle enchantments while attempting other feats of persuasion?
Would your words of endearment seem more authentic when using it to court a potential partner? Would your opinion seem more valid when using it to settle an argument? Would the opinion someone has of you become more likable when trying to dispel doubt in an argument? ... Or will everything sound like an insult?
Though I realize that this does not guarantee the character's desired outcome and the added effects can be negated if they succeed a wisdom saving throw, I'm wondering if it would be a way for a character to increase their chance for a favorable outcome without the other person feeling swindled or used in the end...