I am currently dating a girl and because I am looking for marriage, so I might be engaged in an official relationship with her.

For me I see that any person who suddenly turned into a very religious person (disregarding the religion) might faced some difficulties in his life, big shock, major depression or whatsoever, this girl was normal girl till a certain time in her life, hanging out with friends, watching movies, listening to music....etc

Suddenly she has changed 180 degrees, stopped doing anything that is not allowed in the religion in a very strict way.

I browsed her FB account history since the time she created it, and I succeeded into figuring out the exact time she changed, some people actually disappeared from her account at this time because I found some of her comments replying to people whose their comments are not there anymore which means that they blocked each other for some reason, this point was several years ago.

Emotional shock? I just want to know her history in life.

What is the best approach? Investigation in this way will give just the outlines, but I will never know the story itself.

Asking her to say frankly or what?