apprehensive

ap‧pre‧hen‧sive

worried or nervous about something that you are going to do, or about the future

apprehensive about/of

We'd been a little apprehensive about their visit.

apprehensive that

I was apprehensive that something would go wrong.

Some had apprehensive looks on their faces.

—apprehensively adverb:

'What's wrong?' I asked apprehensively.

There is no need to be apprehensive of him.