How can Toy(Zac efron) do something like that?

my kids frind said that she saw high school musical 4.and it was like this:after the basket game gabriella go`s back to her own calej and troy ask`s Sharpay to marrie him.and wen gabriella see they are kissing she starts crying but she smiles.is it realy an high school musical 4 eny way?and would Troy realy marrie Sharpay?