Before I play the game I heard it's basically pure rape. Is there a way to avoid it? or simply the game begins with rape and ends with rape like no happy ending whatsoever.
You get the choice to have Jenna be perverted or not at almost every scene. The scenes where it's not a choice have obvious story reasons. I'd recommend to just play it and if you don't like it, you can always stop :)
You can also check out the gallery beforehand to check on the content. Enabling skip mode in the gameplay settings lets you unlock the entire gallery right away.