In English, it's common for simple phrase to have more than one meaning. Usually, people can figure out which meaning applies by the context of your remarks.
For example, as you point out, the sentence, "I want to take you for a ride," could mean a few different things, depending on the situation. When a parent says it to a child, it could mean:
- I want to carry you on my back (i.e., I want to give you a piggy-back ride).
- I want to take you on a bike ride.
- I want to take you for a ride in the car.
- I want to take you out in the boat.
Often, the intended meaning is figured out easily enough by surrounding context:
- I want to take you for a ride. Climb on my back.
- Go get your bike helmet. I want to take you for a ride.
- I want to take you for a ride. Let me find my car keys and we'll get out of here.
- Put on your life jacket. I want to take you for a ride.
While it's true that the phrase could mean:
- I want to swindle you.
- I want to play a prank on you.
that seems highly unlikely. For one thing, when you want to "take someone for a ride" in that sense, you don't usually start by announcing your intentions.
A lot of idiomatic expressions are figurative, yet they have literal meanings as well. We can tell someone to "go jump in a lake" even when there is no water nearby. You can "have a blast" at work, and that usually means that you're having a good time, although in rare instances it might mean there was an explosion. Usually the intended meaning is pretty obvious, and, in cases where it isn't, any ambiguity can usually be cleared up with a simple follow-up question:
I want to take you for a ride.
Do you mean in the truck, or on our bikes?