React native async/wait not waiting

I am new to react-native. I am trying to use async/await but it doesn't wait for other function to return response and alert immediately it will not wait 4 seconds. Here is my code Please help me. Thanks in advance:

import {
  AsyncStorage,
  Platform
} from 'react-native';


export const  hello =async()=>{
 const value=await refreshToken();
 alert(value);
 return "adasd";
}


const refreshToken=async()=>{
  setTimeout(async()=>{
    return true;
  },4000);
}