I have pending charges from Ontario (fraud over 5000) and an arrest warrant. I live in Nova Scotia (1800km/1100mi away).
Warrant is provincial (there may be radius too since ON usually does that but provincial at best).

Obviously I want to deal with this, so I am looking into transferring charges to here and pleading guilty (only way to transfer a charge) once a deal is worked out.

My question is, since this is non-returnable warrant, is it really up to an officer weather to arrest me, contact ON PD and after they say no we won't come get her, release me. In a way it makes no sense but I'm curious.

I had to read it several times to find the question. Sorry, I don't know the answer; Canadian laws sometimes can be guessed at, but not in this instance.

"Is it really up to the officer to arrest me"?
Since it's non-returnable warrant.

I live in Ontario and sort of familiar with the law. No, it isn't up to the officer to arrest you. You have to go to the nearest detachment and give yourself in or, live with the warrant over your head until you do. You are facing a Federal offence, so turn yourself into the nearest RCMP office otherwise you risk deterrment; having your passport revoked.

That's the issue, it is Ontario warrant, non returnable, so when I actually asked one officer he said he cannot help me but couldn't say for sure if another officer wouldn't arrest me (traffic stop for example), bring me in an after ON crown say they won't pay to have me sent to ON then release me.

While in Quebec I was pulled over (driving to NS) and officer there told me I have ON warrant, to take care of it and let me go (he said it's ON non returnable warrant).