Repenting of unbelief in Jesus is included in believing in Jesus.
But repentance from sin and then believing in Jesus are two separate acts.
Repentance from sins is not a condition of salvation.
Repentance from sins will not save you.
Only believing in Jesus will save you.
However, ~realizing~ you are a sinner is part of the Gospel: “Christ died for our sins.” 1st Corinthians 15:1-4.
To “repent” means to “change your mind,” about something: about Jesus, about sinning, or about some other subject.