Here's a breakdown:
* Kapayapaan - peace
* ng - of
* isip - mind
Here are some other possible translations, depending on the context:
* Kalmado ang isip - calm mind
* Walang iniisip na masama - thinking of nothing bad
* Panatag ang loob - feeling secure
Ultimately, the best translation will depend on the specific situation and the nuance you want to convey.