Insecure people have a tendency to see gaps in arguments, so structure how you communicate with them in this order:

1. This is what I am certain about...
2. This is what I believe, but am not certain about...
3. This is what I know too little about to have a view on...
...

You want them to think of you as an ally, not a rival. Pay compliments and express gratitude and appreciation: "I admire what you do, and I'm excited to continue learning from you."

While feeling insecure is natural, problematic behaviors can develop when people consistently attempt to conceal or compensate for their self-doubt.

Insecure types are extremely risk averse and unproductive. Some can be downright nasty or display abusive behaviors.

Count the interactions you've had with the insecure person. How many have been bad? All? Half? Less than a third?

You've now answered the most important question: How big is the problem? If you have more good interactions than bad, maybe the person is not that difficult.

Focus on how the outcome of this interaction can create value for the other person. Ask yourself: "What would be a helpful result for them, and what reaction would I like to get?"

Lower their sense of uncertainty by suggesting a trial period, and include clear metrics for evaluating the decision.

For example: "How about we try this for three months and evaluate how it goes by measuring [X] once a week?"

A lack of one-on-one syndication is one reason why strategies fail in companies.

Have a casual meeting with them or suggest a coffee break. Use this as a forum to get to know them.

Working with difficult personalities can dampen our ability to think clearly and make sound decisions.

As a

Think about the negative interactions you've had with them. What topics tend to bring them on? How do you each express yourselves in these situations?

Now think about the good interactions. What is different? 

Prime your mind to host positive thoughts and have their best interest in mind.

One approach I like to use is to remind myself that the that the person is somebody's child. I ask myself: "Would I like someone to have similar negative thoughts about my kids or loved ones?"

Insecure people feel more secure when they have a strong sense of ownership. Structure the work in a series of one-on-ones where both of you should have things to prepare for each meeting.