The hardest things are best said in the softest voice. Volume makes people defend. Gentleness makes them listen.

Force and importance are not the same thing, though they get confused constantly. When something arrives loudly, the body hears a threat and organises a defence, and after that nothing you say is being weighed on merit. Lowering your voice removes the threat and leaves only the content. That is why gentleness works on the hardest subjects.

If the topic is heavy, say it slowly and quietly, and leave space afterward. Sit down rather than stand. Softness here is not weakness, it is what keeps the other person present long enough to hear what you came to say.