I believe there are two levels of forgiveness. First one, the "surface forgiveness", when you simply tell a person that you forgive him/her. This act itself may feel liberating, but at the same time it could only remain among those words that have been spoken without having any deeper effect.
Another level of forgiveness, in my opinion, is way deeper and way more difficult to reach. It basically requires you to dive deep inside your inner world and find out about a part of yourself that was hurt by a person. It may or may not turn out to be a case of some hurtful personal belief about yourself being triggered by another person's behavior. When realization like this occurs, it might as well be clear that there's nobody to forgive - it was all just an internal issue that required your attention to be solved. This is what I'd call a true forgiveness.
Forgiveness isn't just about "I'm sorry", and "I forgive you."
Actions speak louder than words, and forgiveness is one of the most important things to a person. Being forgiven for something is sometimes like a weight being lifted from your shoulders.
A person can choose to forgive the deceiver or not. Forgiveness is the key to happiness - everyone makes mistakes, but by making these mistakes, you can learn from them, learn how to do something differently.
Forgiving a person can sometimes be hard - though everyone makes mistakes and it's unhealthy to hold grudges against people, but sometimes it feels impossible to forgive.
Never lose hope - forgiveness is in everyone.