It's tough to see through a candidate's BS during an interview. Everyone is on their best behavior and tries to present themselves as a slam-dunk hire. 

Employers can try asking questions that reveal a candidate's true character or uncover someone's penchant for narcissism. But these gotcha questions aren't perfect. Bad hiring decisions still get made. Ultimately, it's often the person who performs the best during the interview who gets the job -- and not always the person best suited for the role.

So what's the solution? Web-hosting service Weebly may have found it. The San Francisco-based company includes a critical last step in their hiring process. It helps them dig deep beyond the resume and know without the benefit of a doubt if a promising candidate will go on to become a rockstar employee. Weebly's unconventional hiring process was recently covered by Business Insider.

You can talk the talk. Can you walk the walk?

Before making a job offer, Weebly first asks candidates to work a paid trial week. Weebly CEO and co-founder David Rusenko assured Business Insider this exercise is anything but a cultural fit test. Candidates are given a real project by which the company can evaluate their performance. At the end of the week, candidates present their project to a small group of colleagues. If candidates have performed well during their trial week and have proved themselves to be a good fit, Weebly invites them to join their 300-person team with a job offer about an hour later.

Business Insider reports about 75 percent of candidates ultimately go on to work for Weebly. The other 25 percent? Rusenko says they fall into two camps. One category of do-not-pass-go candidates are those whose skills don't live up to how they portrayed themselves in their interview. They may have talked themselves up as more qualified than they really were.

The other group of thanks-but-no-thanks candidates are people who are just... well... jerks.

"A--holes can hide it in interviews, but for whatever reason, they cannot hide it for a whole week," Rusenko told Business Insider. "I don't know why, but it all comes out within a week."

Though Rusenko describes this trial week as intense, he says it helps Weebly make smart hiring decisions, saving them in the long run. They rarely get stuck with someone who they need to fire later due to performance issues or their high jerkiness factor. It also helps new employees integrate better into teams. When someone shows up for their official first day on the job, their colleagues have already gotten to know them and their working style.