Walk into every argument with a little room for “I might be wrong.” It makes you easier to trust.

Certainty makes people careful with you. If you never arrive with any give in your position, the person opposite learns that talking to you is not a conversation but a wait, and they start keeping things back. A visible bit of doubt is not weakness. It is the signal that what they know could still matter.

Say the uncertain part out loud early in the next disagreement: what you are less sure about, or what would change your view. Keep it specific rather than a general show of modesty. People give better arguments to somebody who might move.