Trust can be there, but it's a process. It's not forever broken. Maybe I'm an optimist but I do believe everyone gets chances. We know everyone makes mistakes and sometimes those mistakes can breach trust, but it can be fixed by BOTH parties. I agree with Belle1979, you have to be open and receptive for it to happen on your part, and the other person has to do their part too.
Expect that your friends to do stupid stuff, and hurt you at least once
Expect yourself to make mistake and hurt them
But it's in their heart to forgive you (and of course, you gotta go on that journey to learn how not to make the same mistake), and it should be in yours to forgive them.
"If you expect your friends to never make mistake and never hurt you, then you will end up friendless at the end". It was an advice from an older person than me, and for me it rings true.
Of course there are circumstances where that person may be hurting you too much to the point where it's very physically and emotionally unhealthy for you, where you'll go through depression, not eating, not functioning, then it's time to part so both of you can learn to become your own person.
In the end, only you can decide whose relationship is important to work on and who isn't. But yes, it takes time, 'cause it's a long process. It's like learning how to walk for both people.