Friendship should contain enough honesty to occasionally become uncomfortable.

Any friendship that has never been uncomfortable is probably operating below its capacity. If neither of you has ever said a hard thing, then what you have is pleasant company, which is worth something and is not the same as being known. Honesty introduces risk, and the willingness to take that risk is much of what makes a friendship load-bearing.

Think of the thing you have been not saying to a close friend. Ask whether you are protecting them or protecting the ease of the friendship. Say it once, plainly, and let them have their reaction.