It would actually depend on if they were genuine in their apology and how bad the betrayal was.

I might be forgive them if they apologize, but I won't easily trust them again.

Depends on the situation.
But this is targeted to one guy in particular. HE WILL NEVER BE TRUSTED. ARSE!
Kicu, seuno yen ter hat Quyoneihke....weil er blöd ist!

Maybe later if they showed that they were sorry.

No.
Because last time I gave someone a second chance they just betrayed my trust again.
Not worth the headache. But I would forgive them, possibly.

Never. I hold a grudge like you wouldn't believe and my trust isn't something I give freely which makes it all the more insulting when it's abused by someone.

Though it does depend

This depends entirely on the person in question, what they did in the first place, and what they did to make up for it.

I do hold grudges easily, and there's a few that I have over things that happened ages ago that aren't going anywhere anytime soon. But for someone really close to me- someone irreplaceable- I could set that aside and work towards regaining the trust I'd lost. There's a few people in my life that would be worth it.