Change your Google account to US account permanently

• Login to your account normally .
• Open this url 
•  on Google Store credit section click the button labeled set up 
• Enter 10007 as your zip code then click continue.(if you check your Google account in the browser you will see that your country has changed) 
• Download any vpn app and choose us server (this action need to be done once a time then you can delete the app) 
• Go to settings > application on your Android phone and wipe data of both Google play services and app store
• Open app store while vpn app connected on the US server, go to account > preferences and choose united States. 

You can delete the VPN and your account will stay us account. 
Note 
You should know that this action might be permanent, and you can't undue this action (your country will stay United States) .