Ok, Catholics beieve that there are 2 things necessary for Salvation:
1. First and most important of all, you must accept Jesus Christ as your personal Savior and repent from your sins
2. In result of this, we must be the best Christian we can be. IE: By doing good works, pleasing God, obeying the Gospel, abstain from sin, etc..
Now, Catholics believe that if you reject Christ and expect to be saved through good works, you will not attain Salvation. You must do good works and be a good Christian not for the reason of attaining Salvation, but we do good works because we want to serve and obey God, and God commanded us to do good works. We believe that if you do no good works and be evil, you will be blured from the truth of Christ and the Holy Spirit will leave your soul. Therefore, you may think you believe in Christ, but deep down you do not. That can only happen by doing evil works and disobeying God.
We should do good works just to please God and obey him, Not to get to heaven. We believe Jesus died for our sins, but if we let Jesus pay our price, we must now become one with Christ also. We do this by obeying and pleasing God by going to mass, praying often, doing good works for your neighbor, etc.
As far as the sacraments go, We do the sacraments to greatly streangthen our relationship with Christ and God, and it is just another way of pleasing God. While the Sacraments are Very importent to us, you may not lose your salvation over it. Especially if you are a sincere believer in Christ, you may be saved.
Now if you are confused over why Paul has said sometimes that you need just faith and no works, and other times he says we need works with faith. This is how we explain it:
There are 2 types of Good Works:
1. Works in the system of Law
2. Works in the system of Grace
Works in the system of law pretty much is doing good works with you expecting God to repay you for it. IE: heaven, blessings, etc..
If you do good works this way, you will not attain salvation, because all have fallen from the glory of God.
Works in the system of Grace is doing Good Works and obeying God without expecting anything in return and just obeying and pleasing him in faith and love. If you do good works and obey God in this way in addition to repenting for you're sins and accepting The Lord Jesus Christ as your personal lord and savior, you can be saved.
So what is your view?