A lot of people are believing in Jesus, some of whom in private. Jesus later made a comment on believing in Jesus.
First off, Jesus proclaimed that when someone "believes in [Him]", that person "believes not in [Him] but in Him who sent [Jesus]" (12:47). That statement at first seems perplexing, so let's analyze it. In the statement, Jesus is employing a "limited negative" where the phrasing "not A but B" actually means "not only A but also B" (Patheos). This phrasing is supported in the AMP, ISV, MEV, NIV, and NLT translations. With the phrasing, Jesus meant that whenever someone believes in Jesus, that person also believes in the one who sent Jesus (especially since the Father directs the process, not to mention that both Father and Son are God as described in John 8:58). Jesus also proclaimed that all believers would not abide in darkness (12:46). Eventually, every believer would be with Jesus, and from John 1, Jesus is the light. No darkness there!
Additionally, Jesus proclaimed that regarding people who reject Jesus, at least at this time, Jesus does not judge (punish) them because his focus is on saving people (12:47). Rather, Jesus talks about how their rejection and Jesus's word punishes them (12:48). In other words, people are affected themselves by their own rejection of Jesus because unbelief keeps them from experiencing the light that is Jesus.