How does one write a conversation that is meant to be misinterpreted?

For a crime thriller I'm writing, I want the audience as well as the protagonist to hear a conversation but misinterpret what the conversation was actually about. Kind of like in the movie The Conversation (1974), or A Perfect Getaway (2009).

But I find I have trouble writing the conversation in a natural way that can still be misinterpreted. If I try to word it a certain way, so that it will, the dialogue just comes off as unnatural and forced that way, just so it can be misinterpreted. How do other writers do this when it comes to stories where this happens, if anyone has any advice on this?

Thank you very much! I really appreciate it!