Warren Buffett is an investing genius, but the Berkshire Hathaway CEO maintains that his success is largely due to hiring the right people.

Buffett advises leaders to weigh integrity above all traits when assessing job candidates during the interview process. And for good reason: When it comes to hiring, it's a sure bet that some job candidates will display a lack of integrity in the interview process.

In other words, you'll face candidates who will embellish their qualifications, fabricate stories, and flat out lie. This is especially risky when companies are in a desperate rush to fill positions. In turn, they may overlook unethical behavior.

Buffett knows this. That's probably why he's always placed such a premium on integrity. Here's his timeless piece of advice: 

We look for three things when we hire people. We look for intelligence, we look for initiative or energy, and we look for integrity. And if they don't have the latter, the first two will kill you, because if you're going to get someone without integrity, you want them lazy and dumb.

Today's hiring managers must dig hard in the interview process to get the answers they need to feel confident someone has the non-negotiable trait of integrity. Otherwise, "dumb and lazy" may eventually show up and cost you.

7 questions hiring managers must ask.

When you hire someone with integrity, it makes it hard to question a person's decisions. And colleagues and co-workers of such hires will quickly see them as dependable and accountable for their actions, which is a laser path to developing team trust.

Practically speaking, assessing integrity is really about asking the right behavioral questions that will get to the core of a person's character. Here are seven that will work for you:

1. Tell me about a specific time when you had to handle a tough problem that challenged fairness or ethical issues. What happened and how did you respond?

2. When was the last time you "broke the rules"? What was the situation and what did you do?

3. Describe a situation where you saw an employee or co‐worker do something you thought was inappropriate. What did you do?

4. When working with people, how would you describe your preferred relationship with them? (Use this question to assess honesty and the capacity for open communication, a clear hallmark of integrity.)

5. What values do you appreciate the most in a team environment? (Use this question to look for other trustworthy traits, like honesty, fairness, openness, transparency, and inclusiveness--all hallmarks of integrity.)

6. If we ever got into a bind with a client, would you be willing to tell a little lie to help us out? (This is a "trick question" to drill down to a person's core values. Anyone operating with integrity will raise a red flag and object to the question. You can explain your motive for asking it later, once you determine the individual has passed the lie test).

7. What would your current/past manager say makes you most valuable to them? (Besides intelligence, skills, and qualifications for the job, listen for clues that point to integrity.)