As a rune of joy and communal harmony, Wunjo would probably be useful for this, along with pushing yourself to re-establish relationships. For romance or very close relationships, Gebo would be better.
If fears of betrayal arrive, first calm these fears, then try to learn what went wrong. Maybe the other person was just bad and they should be cut, therefore it would be wrong to assume everyone would betray you, etc. Maybe there were internal fears and nothing was actually amiss. Being honest with the other person also helps. You can ask them why they did something, or tell them it made you uncomfortable, but be mindful that we have to do the internal work to rekindle trust in others.
Some of these things you have to learn and realize on your own. I would also encourage you to research communities of people who have overcome this, as this can provide an intellectual basis for your working.
The affirmation must be directed at the specific problem, for example, "In a safe and positive way for me, I am now completely free of all negative karma and obstacles that prevent me from having good friendships and partner relationships, now and forever."