Most secure web app builder that is still easy to use

Pretty much how to make a web app which is secure (the database will contain a lot of personal information). yet is still be doable by someone who is only self taught in one or two languages (and has no experience whatsoever in security) .

Just want to know which program/library to use/learn (so the app isn't half done and then find out the program/library can't do the job well).