How can we trust the police when they don’t trust us?

You can't ,but you can't live without them either.....not all are bad ,but you have no way of knowing just which ones are....Just one bad apple can start to whole bag rotting....:(

we might not be able to

I don't, regardless.

Police are sworn to enforce the will of the legislature. They have no duty to citizens.

The only purpose of a government is to prevent any other group from taking control. The duty of a citizen is to control his government. That is why governments always eventually treat citizens as enemies of the state. And cops are the soldiers in that war. There are no "good" cops. They are your sworn enemies right from the start.

They have no reason to trust us.

Because they are the ones with the guns.