Not currently. Once you respond with "Trust", you cannot change it. If it's not prompting you now when you connect, it means you have chosen to trust it before.
Snippet from the end of this Apple support article titled "iOS: 'Trust This Computer' alert":
Additional Information
Note: If you select Trust, the computer will be trusted indefinitely. If you select Don't Trust, you will be asked if you want to trust that computer each time you connect your device to that computer.
Last Modified: Sep 18, 2013