A former FBI hostage negotiator says these 2 words are crucial in any negotiation

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Whether you're buying a car, negotiating your salary, or deliberating with your partner, you'll want to hear more than just "yes" from your adversary.

"The sweetest two words in any negotiation are actually, 'That's right,'" says former FBI hostage negotiator Chris Voss in his book, "Never Split the Difference." "Before you convince them to see what you're trying to accomplish, you have to say the things to them that will get them to say, 'That's right.'"

These two words can create breakthroughs and allow the negotiation to proceed from deadlock, he explains. "When your adversaries say, 'That's right,' they feel they have assessed what you've said and pronounced it as correct of their own free will. They embrace it."

At the same time, they don't feel like they're giving in, which is key.

"The 'that's right' breakthrough usually doesn't come at the beginning of a negotiation," Voss says. "It's invisible to the counterpart when it occurs, and they embrace what you've said. To them, it's a subtle epiphany."

Getting to "that's right" may be a winning strategy in any negotiation, but hearing "you're right" signals disaster, Voss warns.

"Consider this: Whenever someone is bothering you, and they just won't let up, and they won't listen to anything you have to say, what do you tell them to get them to shut up and go away? 'You're right.' It works every time," he says. "But you haven't agreed to their position. You have used 'you're right' to get them to quit bothering you."

On the other hand, "that's right" signals understanding. "The power of getting to that understanding, and not to some simple 'yes,' is revelatory in the art of negotiating," Voss writes. "The moment you've convinced someone that you truly understand her dreams and feelings, mental and behavioral change becomes possible, and the foundation for a breakthrough has been laid."

The bottom line: Don't just try to get to "yes" strive for "that's right."