A heart-to-heart is a private talk in which two people say what they really feel, without covering it up. It is not a meeting, not a quarrel, and not chat about the weather. You sit down — on a bed, on the stairs, in a parked car — and you stop pretending. You might talk about a fear, a hurt, or something that has been sitting between you for a long time. English likes the verb have: have a heart-to-heart, have a heart-to-heart talk. The phrase can also sit in front of a noun: a heart-to-heart conversation. It feels informal, warm, and a little serious. Friends do it, couples do it, parents and children do it. You would not usually call a speech to a class a heart-to-heart; the picture is two people, or a very small circle. Though actually, one person can do most of the talking while the other mostly listens — the point is honesty, not equal time. In careful or formal writing, people may say a frank conversation instead.