Peace is an absence of conflict. So inner peace is to no longer be in conflict with your inner state. To no longer judge, to no longer attempt to control whatever the inner reality is, and instead allow it to be, without taking responsibility for it.
If you can see that thoughts, emotions, feelings, pleasure and pain are spontaneous appearances, that you do not decide to create, then you no longer need to take yourself to be the personal controller of any inner movement or experience, and so whatever disturbs or creates conflict inside can not stay for long.
In this relinquishment of inner manipulation, you may notice that there is no personal thinker of thoughts, no personal producer of emotion, no personal sufferer of pain, and no personal enjoyer of pleasure. The little, personal self (the ego) is seen to be illusory, and it drops away. Then we are aware of the deeper existence, the Life beyond form, without which no form could exist. This Life, existence, is not separate from who you are.
So, you don’t have to search for or find inner peace. Instead see that the conflict with your present experience is quite futile, that it does not heal or truly resolve anything. Your present experience, whatever it may be, already is as it is. If you give up arguing with it, you see it is not really “your” experience – the person who feels they are suffering from the experience is seen to be just another thought. Your own sense of existence remains untouched.
It is the personal mind that masks natural inner peace. The imaginary personal self feels it is in control, responsible for each thought and feeling, and that Life is somehow its own responsibility. Relinquishing your control over your inner state exposes this personal self to be merely imagination, and that peace is not far away – it is one with existence, from which the personal self arises.