I have tried every type of garden hose end to repair an old 3/4 fitting and evryone has leaked either at the hose or at the rubber washer, I have heard that pex clamps will do it the first time, is this correct?
What is your water pressure? Your water utility should be able to measure it for you (you may need a [new] regulator to keep it down to something less than 60 PSI or so.)
PEX is a modern small piping solution with kinda specialized fittings and clamps for the PolyEthylene tubing, but this shouldn't need that.
Stainless steel hose clamps (but avoid any that aren't ALL stainless, they'll rust quickly and be a bear to replace). Size to suit the diameter of that hose.
You didn't mention which end, but a common leak is around the female end (that screws onto the faucet bib), where it allows the connector to rotate.
Good luck finding one, US made or high-quality import, that wouldn't leak there, but once put together right and secured down, it shouldn't (much). Some even have an extended support sleeve for Strain Relief.
Trim the hose end back to good material. Maybe stick the end in boiling water to soften it, if it's tight (use dry rags to avoid scalds!), put the clamp on FIRST, then the new fitting, all the way in.
Tighten the clamp with a nutdriver if you can, or (carefully) with a screwdriver, against something you don't mind scarring with a slip (NOT your other hand! -Hint, hint.)
Let us know how it all works out!