Belief
Amplified Bible

Romans 10:9

Because if you acknowledge and confess with your lips that Jesus is Lord and in your heart believe (adhere to, trust in, and rely on the truth) that God raised Him from the dead, you will be saved.

Genesis 15:6

And he [Abram] believed in (trusted in, relied on, remained steadfast to) the Lord, and He counted it to him as righteousness (right standing with God).