Both Parents and Godparents will be expected to affirm the following promises (which is why people of other faiths (and none) cannot be Godparents) - oftentimes in these situations parents will informally ask these persons, to be more of a guardian/role model privately to the child - the promises are:

Priest: If your faith makes you ready to accept this responsibility, renew now the vows of your own baptism. Reject sin; profess your faith in Christ Jesus. This is the faith of the Church. This is the faith in which this child is about to be baptised. 
Priest: Do you renounce Satan? 
Parent/s and Godparents: I do. 
Priest: And all his works? 
Parent/s and Godparents: I do. 
Priest: And all his empty show? 
Parent/s and Godparents: I do. 

Now I ask you all:
Priest: Do you believe in God, the Father almighty, creator of heaven and earth? 
All: I do. 
Priest: Do you believe in Jesus Christ, his only Son, our Lord, who was born of the Virgin Mary, was crucified, died, and was buried, rose from the dead, and is now seated at the right hand of the Father? 
All: I do. 
Priest: Do you believe in the Holy Spirit, the holy catholic Church, the communion of saints, the forgiveness of sins, the resurrection of the body, and life everlasting? 
All: I do. 
Priest: This is our faith. This is the faith of the Church. We are proud to profess it, in Christ Jesus our Lord.

Amen