O my God, I am heartily sorry for
having offended you, and I detest
all my sins, because of Your just
punishments, but most of all because
they offend You, my God, who are
all-good and deserving of all my love.
I firmly resolve, with the help of
Your grace, to sin no more and to
avoid the near occasion of sin. Amen
Act of Contrition (Modern)
My God, I am sorry for my sins with all my heart.
In choosing to do wrong and failing to do good,
I have sinned against you whom I should love above all things.
I firmly intend, with your help, to do penance, to sin no more,
and to avoid whatever leads me to sin.
Our Savior Jesus Christ suffered and died for us.
In His name, my God, have mercy.
Either of the above Act of Contrition is fine to learn. The Act of Contrition is prayed after a confession. The prayer should be said with a full contrite heart to all of the sins you have just confessed.