Many view trust differently and come to trust people differently. Some trust from the very first minute, while other trust no one until given a reason. Whether you trust completely or wait for a reason, when trust is gone, it's gone and it's very difficult to get back.
Often, the largest reason people lose trust for another is due to lies that have been told. When this happens, there are many times that trust can be reestablished as long as the lying stops and positive steps are made towards the future. However, when lies continue to accumulate, the ability to trust again slips further and further away.
Many times, the one who is guilty of the lying tries to rebuild the relationship by appearing to be a different person and making an effort to be better than before. However, if the person truly hasn't changed, they have to display a persona to make it appear as though this new changed life or outlook is actually their reality.
Unfortunately, this is still lying and in no way helps establish trust. It doesn't matter if they are little white lies, moments of deception, full blown outright lies, or leaving out necessary details. Often, the guilty party feels successful with the lies they have told, but they are transparent and aren't fooling anyone. This makes it nearly impossible to ever rebuild trust.
If you're worried about hurting someone again after trust has been lost, stick with the truth no matter what. Even if your honesty may be hard to hear or unflattering, it's more respectable than lying to cover things up.
Once trust is gone, it's gone.
It's must easier to lose trust than it is to regain it. Don't put yourself in a position to be considered untrustworthy.
Should you find yourself on the receiving end of lies that have fractured your trust, be open and accepting, but be wary not to be hurt again.