Praying an Act of Faith is just a way of acknowledging God’s goodness and sovereignty over our lives.  These Acts of Faith are most valuable and effective, ironically, when we have a LACK of faith.  “Fake it till ya make it” can be a method to meet the Lord when we are feeling weak, like the father asking Jesus to heal his sick child  in Mark 9:24 seems to make an assertion and a request at the same time, “Immediately the father of the child cried out, “I believe; help my unbelief!”

Here are a few examples:

Jesus, I trust in you (turning to the example of St Faustina in the Divine Mercy Chaplet)

O my God, relying on Your almighty power and infinite mercy and promises, I hope to obtain pardon of my sins, the help of Your grace and life everlasting, through the merits of Jesus Christ, my Lord and Redeemer. Amen (Catholic Online)

O Lord God, 
I hope by your grace for the pardon 
of all my sins
and after life here to gain eternal happiness
because you have promised it 
who are infinitely powerful, faithful, kind, 
and merciful. 
In this hope I intend to live and die. 
Amen. (USCCB)