You say it so that it can be heard
Sun in Libra in the 3rd house puts your talent into ordinary talk: you frame things so people can accept them, you soften without lying, and disagreements around you tend not to escalate. You need daily contact with people rather than a life conducted in writing.
It is a genuinely rare skill and it has a specific hazard. A message shaped for acceptance sometimes arrives so smooth that the actual content goes unnoticed, and you find later that nobody heard the part that mattered.
You end up mediating things that are not yours
Two colleagues who are not speaking, a family group where somebody has to be the channel, friends who have fallen out: you are drafted into these because you are good at it. Take on the ones you choose and decline the rest plainly. A permanent mediator gets blamed by both parties eventually, which is the standard fee for the role.
The blunt sentence that never gets said
There is usually one thing you have decided not to say because it would be too direct, and it has been outstanding for months. The softening you are planning will not make it easier, only longer. Say it in the plainest available version, once, and then stop talking. Your delivery is good enough that plain will be received better than you fear.
Hearing both sides is not the same as having a view
You can construct the opposing case better than most people can construct their own, which is a genuine intellectual strength and an excellent hiding place. Somebody will eventually ask what you think. Decide before you are asked: write the sentence down, privately, so that you are not composing your own position while under pressure to be fair.
Writing lets you land it properly
Given a draft you can find the phrasing that makes a difficult message acceptable, and it is one of the most useful things you do. Use it deliberately: write the hard message rather than improvising it, and read it once for whether the content survived the courtesy. If it did not, put the content back in.
The person sent into the difficult meeting
Wherever a relationship has to be repaired or a message has to land without a rupture, you are the one who gets sent, and it works. Make that an explicit part of your role rather than an informal favour repeatedly asked. Skills that stay informal never appear in a salary band, and the person doing them is the last to notice.
The go-between everybody trusts
You hold information from both sides of most disputes in your circle, which makes you valuable and puts you in an impossible position when it escalates. Decide your rule in advance: what you will carry between people and what you will refuse. Announcing the rule early is what keeps the friendships intact.
Keeping the peace at the table
From early on you were probably the one who defused things, changed the subject or made everybody laugh at the right moment. That was a considerable job for a child and it is still running. Notice when you are doing it out of habit rather than necessity, and let one small tension go unmanaged.
The conversation you keep rehearsing
Unsaid things run in the background here as endless rewriting: the message drafted, deleted, drafted again, at eleven at night. It costs you sleep rather than mood, which is why the tiredness never seems connected to anything. Set a rule that anything rehearsed more than twice gets sent or dropped by the end of that week, in whatever state it is in.
Plainness as a skill worth acquiring
Your fluency lets you avoid directness indefinitely, so directness has to be practised on purpose rather than arrived at naturally. Choose one relationship where you will say things plainly for a year. The tact will still be there when you need it, and you will have something you did not have before.