Paul writes that if you believe in your heart, you are justified. The Oxford English Mini-dictionary defines ‘believe’ as ‘accept as true, think, suppose’ and ‘feel sure of the worth of.’ And, the same dictionary defines ‘justify’ as ‘show to be right or reasonable.’ So, if you are sure of Jesus Christ, if you accept Him as being true and worthy, you are shown to be right. You are reasonable, having come to a correct conclusion.
Paul further writes that if you confess with your mouth, then you are saved. Webster’s Vest Pocket Dictionary defines ‘confess’ as both ‘acknowledge one’s fault or misdeed’ and ‘declare faith in.’ The same dictionary defines ‘save’ as ‘rescue from danger, guard from destruction, redeem from sin’ and also ‘set aside as a reserve.’ So, if you acknowledge your need for salvation and your faith in Jesus Christ and His provision for that sin, then you will be set aside for God who then guards you from destruction, rescues you from danger, and redeems you from your sins.