....or.
Buy a dog.
Kill it.
Chop it up and feed it gradually to stray cat, thus winning its trust.
Give it some sweets
There's not much you can do, it sounds like this particular cat has reason to be very cautious of humans, but lets not go there shall we?
It takes months to break that kind of fear in a cat, cat's generally adopt this caution due to events and trauma and it takes a lot to break it, but it can only be reduced dramatically, once they're struck with this kind of fear, it never goes away completely.
Just keep feeding it outside, that way you get a Cat without it stinking up your house! Win-Win!
Cue: All pet owners posting frantically denying their homes stink of pet-stink!![]()
Do you want a pet or to help it? There's a difference.
Give it food and even put out some warm dry bedding (if it gets wet then change it/wash it). The key thing is you're expecting it wants to be domesticated.