Communicate boundaries directly

State the boundary plainly and respectfully, owning it as yours rather than as an accusation.

Why it works

Hinting or hoping someone will guess your limit usually fails and breeds resentment. Stating the boundary directly, in "I" terms, gives the other person clear information to respond to and keeps it from landing as a character attack, which would trigger defensiveness instead of change.

How to do it

1. Use "I" language: "I’m not available for calls after 9pm."
2. State the limit once, plainly, without apologizing for having it.
3. Pair it, where useful, with what you can offer instead.

Evidence

Direct, "I"-framed communication is supported by assertiveness and communication research as reducing conflict relative to passive or aggressive styles. (clinical)

The communication principle is well established clinically; outcomes depend heavily on the other person’s response, which you don’t control.

Common mistake

Expecting people to intuit your boundary, then feeling betrayed when they cross a line you never actually stated.