Return a value from a promise

I'm still learning web development and have researched promises and I feel I have a basic understanding of it but am still failing to return a result. I'm sure this is something already answered somewhere in the confusing world of Stackoverflow but I have not found anything useful.

Stackoverflow link: for those who like linking to other articles

I tried the then function in that article in various ways and still am only receiving a promise result.

The function below is where I am hoping to receive a result. I am calling the datePresent function which returns a promise. After the promise is returned it should return a boolean

function resultBoolean(){

  return
  datePresent().then(function(result){
  return result;
  });
}

datePresent Function

function datePresent(){

  var date = "07-10-2018";
  var id = "SWSyWAJlkVDqSIzrcHdm";
  var documentReference = 
  db.collection("clients").doc(id).collection("sessions").doc(date);

  return documentReference.get().then(function(documentSnapshot) {
    if (documentSnapshot.exists) {
      return true;
    } else {
      return false;
    }
  });
}

Maybe I am not comprehending promises.