As a healer I encourage and support my clients to reveal the inner resources needed to let go of any resentment, anger or pain associated with past emotional trauma but as a human being I can easily understand how difficult this can be.
My strategy is based on three principles that in most cases facilitate engagement. One is understanding the dynamics of resentment. The second is the differentiation between remembering and forgiving and the third is accepting the offender consciousness.

The Dynamics of Resentment
Resentment is the holding on of negative emotions as a result of real or imagined wrong done. Typically, negative emotions are bottled up, stored somewhere in the body causing a festering affect that gradually poisons every aspect of one’s life.
The saying that resentment is like drinking poison and waiting for the other person to die is more accurate than we’d like to admit. When you hold on to grudges, anger or pain you can be sure that it will poison your system, often to the extent of emotional paralysis and physical disease.

Resentment gives power to the offender because it keeps the memory charged and active. Resentful people relive the painful memory on a regular basis, constantly refueling their resentment. A vicious cycle with extremely negative ramifications to emotional and physical well-being therefore considered one of the most self-defeating emotions there is.
The first premise for suggesting forgiveness as a valid alternative is that resentment  has no effect what so ever on the offender. It’s an inner dialogue that emotionally, psychologically and physically undermines the victim. Forgiveness is a pro-active choice made out of the realization that in order to be in the driver seat of one’s life ones must regain power over ones’ destiny and what affects it.

Differentiation Between Remembering and Forgiving
Technically speaking memories can’t be erased and I’m not sure it would be advisable to erase memories even if we could. Past experiences are an extremely significant resource for personal growth, conditioned that one learns from them and modifies responses in future situations.

Utilizing memories as a platform for change is very beneficial. Allowing memories to poison the system is not.  The element that determines the effect memories have is the emotional charge associated with them. Once the emotional charge is de-activated, the memory can be used as personal leverage.
Forgiveness can occur once the emotional charge is released. This doesn’t imply that the memory is gone or that the event never happened or that it was insignificant. It just means that one chooses to store the memory in a different form- more emotionally neutral for the purpose of healing.

Accepting the offender’s consciousness
Once the emotional charge is de-sensitized, its easier to accept that the offender was motivated by what he or she perceived as the only possible action.
Their higher Self most likely new that their actions were wrong but the aspect of themselves manifesting in reality was one that new no other way and lacked the inner resources to act differently at the time of the offense.
This approach differentiates between people and their behavior, not justifying wrong actions but putting them in a perspective where levels of consciousness are recognized as significant factors in the creation of behavior.

This is also no doubt the hardest aspect to convey to victims, however in most cases, when the two previous strategies are accepted, with time, this one will be accepted as well.

Forgiveness does not make it right
Equally important is to stress that forgiveness doesn’t make the offense right and it doesn’t free offenders of their responsibility. Realistically the victim has no influence over the offender’s willingness to take responsibility therefore perceiving the offender or the offense through that lens is completely irrelevant.

The only purpose in the process of forgiving is to free the victim and promote healing. This can be achieved by applying the above strategies. Although not necessarily easy to do, emotionally de-charging past emotional trauma and ultimately forgiving is vital for healing. That and only that should be the motivation and source of strength.