I always loved this line from the recent remake of Pride and Prejudice:

Elizabeth: I wonder who discovered the power of poetry in driving away love.
Mr. Darcy: I thought poetry was the food of love.
Elizabeth: Of a fine, stout love. But if it is only a vague inclination, one poor sonnet will kill it.

I don't remember it being in the book, but I could be wrong.

Transparency is something needs to be developed between people. You don't start out with that level of intimacy, ever. There are far to many nooks and crevices in a personality to discover it quickly.
And having transparency with someone is something that must be constantly tended. It's far easier to bare your soul to a casual friend than it is to someone who's opinion truly matters to you, because their judgments are far more impactful to your ego.

It can be just as hurtful to give too much information as it can be to not give enough. It's a balancing act. In the end, people bounce. We're remarkably resilient that way.

You might also look into the book "Crucial Conversations." It deals with both business and personal confrontations, though more focused on business.