Deciding who to partner with — either as an individual executive or as a business — is a choice that comes with a lot at stake. To be absolutely certain they’re doing the right thing for the business, leaders should pick people they’re confident they can rely on and trust to do the right things for the good of the company. In business, as in life, the best partners are honest, reliable, and contribute something we otherwise wouldn’t have.

In business partners we (must) trust
Leaders today sometimes build their companies using the same strategy you might apply to solving a jigsaw puzzle: Grab the first piece that looks right, shove it in, and then see if it fits. If it doesn’t work, you just try again. But deciding which partners to involve in your business can have a huge impact on its overall success and the cost of a bad partnership can be astronomical.

That’s why anyone looking for a new business partner must prioritize two traits above any others: trust and reliability. Other characteristics and skills are also important, but these two are the barrier for entry. Trusting a partner depends on whether or not he or she can put the company first and keep its strategy and plans confidential. Reliability is all about prospective partners keeping their word and doing the things they’ve committed to deliver. Trust and reliability are the foundations for the rest of your relationship, which needs to be solid in order for everything else to work.

You can’t judge a book by its cover, so find a partner who’s an open one
Trusting the people you collaborate with doesn’t just mean knowing they won’t divulge company secrets — it means knowing they’ll be honest in all things, especially around the hard topics. Once in a while, every leader has to face some unpleasant truths — even when it comes to his or her own work — and that’s a good thing.

More eyes also equals fewer missed details — as long as those eyes come with mouths, too, to point something out that might have slipped by you. A good partner talks about the way things really are, tells you when you’re doing something wrong, and helps make you better. A great partner wants the same in return, but doesn’t get defensive. Work with people and companies you know will keep you in the loop about what’s going on and will offer useful feedback. Open, communicative people and partners are a huge asset.

See also: The real reason 65% of startups fail

Many companies make the mistake of partnering with businesses or executives who say the right things instead of the ones who deliver results. Long term, these yes-men and people-pleasers erode teamwork and trust. They’re far less useful than partners who opt to identify sticky issues before they become bigger problems.

Opposites (should) attract
Partners should add something unique and valuable to the relationship. Find people or companies that complement your strengths or weaknesses and shine brightest where you don’t.

Look for folks who are willing to say they don’t understand something rather than just go along for the ride, yet are still mart enough to understand different aspects of the business. Diversity of style is key when it comes to partnerships. Teams of people who are introverts, extroverts, optimists, and even pessimists think differently thanks to their unique perspectives, and will make better decisions than homogenous ones ever could.

When you find yourself in the market for a partner, whether it’s an individual or a business, prioritize trust, openness and diversity in deciding who can truly add value to your company. It’s one of the most important choices you’ll make, so be sure to treat it that way.

Read all responses to the Leadership Insider question: What do you look for in the ideal business partner?

Why you keep picking the wrong business partner by Tom Gimbel, CEO of the LaSalle Network.

Why friends make terrible business partners by Todd McKinnon, CEO of Okta.

What you need to know before choosing a business partnerby Clark Valberg, CEO of InVision.

Never pick a business partner based on their skills alone by Pau Sabria co-founder of Olapic.

Business lessons from Iraq: How to create a dynamic team by Chris Fussell, chief growth officer at McChrystal Group.

Dolby CMO: What Star Wars taught me about finding business partners by Bob Borchers, senior vice president and CMO at Dolby Laboratories.

The quickest way to sabotage your new business by Jim Yu, CEO of BrightEdge.

How to avoid picking the wrong business partner by Ryan Harwood, CEO of PureWow.

3 signs you need to ditch your business partner by William Craig, founder and president of WebpageFX.

The most important relationship you will make in your career by Nirav Tolia, CEO of Nextdoor.