How can i know truth about that person to whom m going to get marry.?

Coz we can know about the persons when we talk with that person for few days.bt for marriage we talk only few minutes.then in few minutes hw can i judge that person.it happened wid me two tyms.after engagement i found the reality.and i said no for that relation.i dnt want it again in lyf.so plz suggest me.t i found the reality.and i said no for that relation.i dnt want it again in lyf.so plz suggest me.