What's the most reliable way to go from copper to pex without soldering?

Just curious to hear what you think is the best way to go! I know a lot of people wouldn't consider not soldering, though.

I normally solder on a PEX adapter to copper pipe.
However if you're not soldering, then you are looking at a sharkbite.

Been very happy with my SharkBite adapters so far. Are you not trying to solder because of tight spacing or things nearby?

To be honest, I have none of the stuff required and it's gonna be kind of expensive. That, and I have no experience soldering, and I want to get this project done. Thanks for all the info!

Basic soldering "stuff" is not expensive. All you need is a propane torch, a can of flux, a tubing cutter, a roll of solder, and a roll of emery cloth or brushes to clean the pipe ends and fittings. Sweating joints is not a difficult skill to learn, even if your first efforts don't look pretty, they will work. A few practice fittings and a little pipe is all you need to learn.