The Best Dua for Laylat al-Qadr…
'Aa’ishah (ra) said: “I said, ‘O Messenger of Allah (saws), what do you think, if I witness Laylat al-Qadr, what should I say?’ He said: ‘Say, O Allah, You are Forgiving and Generous, and you love forgiveness, so forgive me.’” (Ahmad, al-Tirmidhi and Ibn Majah)
i.e.
** “Allah-huma In-naka afu-un kareem-un tuheebu aff-wa-fa-fu-an-na”**