There's more to communication than the words you choose.
A professor of mine once described the brain like this: "Imagine that you have covered every inch of the exterior of the two towers of the World Trade Center with windows. Now stack television screens in those windows so that every inch of window pane reveals a television screen behind it. Now, imagine all of the individual pixels on the individual screens behind all of the individual windows on every floor and every side of both of the towers. That is how many neurons we are talking about when we talk about the brain."
Every one of those little puppies fires, on or off, inhibitory or excitatory signals, and the tubes (axons) they fire along are of varying sizes and connected to hundreds and thousands of other neurons.
A thought is a pattern of activation across those neurons and axons, from layer to layer in an insanely complex dance.
When we write we approach the world as though it were handicapped, capable of receiving information only visually. Chronic writers, no matter how talented in metaphor and simile, still approach the world as representable purely linguistically. Words on a page.
Words in your ear are something else. So many more neurons in their little neural communities are involved in hearing spoken words than in reading written words. So many more are involved in feeling the breath on your neck or seeing the look on a face when you speak directly to someone.
It ought to be unsurprising that the thoughts elicited in direct communication are more complex than those elicited by the written word. Not better, just more complex, involving more transitions.
But with this increase in complexity, and an increase in our ability to sift through that complexity with practice we lose something, or gain something, when we transition from writing to speaking. Writing is excellent for conveying honest thoughts, but sincerity is best conveyed in person.
Sincerity is honesty with feeling. And our feeling-detectors work much better face-to-face. It's difficult to be sincere in writing, because all of that feeling of sincerity you have while you write is going to be diluted by the starkness of the written word. Writing is almost an impediment to conveying sincerity. Your reader has to be able to put him or herself in an emotional state that isn't built in to the words themselves; there are no triggers, so you just have to hope that your reader has that kind of empathy. In person we can take advantage of those more subtle tools of communicating sincerity: eye contact, head-angle, light touches on the arm or grasping hands, tone, rhythm, and cadence.
And if you are speaking with someone and they fail to take advantage of these extras that come with speaking in person you experience something like the Uncanny Valley: a point at which the person seems less genuine, less of a person, uncanny, and disturbing. Alcohol and other aids to lowering barriers often increase honesty at the cost of sincerity. The ratio favors the uncanny valley, and turns the drunk into an honest non-person.
Honesty is important. Erin will learn how to be honest. But sincerity is even more important. The difference between charm and cheese is sincerity.