What are some things VCs look for during pitches that instill confidence in them about the startup founders’ pitching?

We want founders that have a unique insight into a large market and are fundamentally driven to bring their solution to life. During the actual pitch, I also want to see someone that is extremely confident in their vision but also recognizes their weaknesses and will be able to flexible along the way and able to hire a team that fills those gaps. I like to ask what keeps them up at night or what they see as their biggest challenge, if they say nothing, it basically means that they haven’t thought it out or they are lying since every company faces enormous challenges and nothing ever goes according to plan.