What do "undramatic" and "set in" mean in this paragraph? Here is paragraph: "Anyone who believes rejection is not quick, painless, and undramatic needs to experience it more times so reality can set in" What do "undramatic" and "set in" mean in this paragraph? Thank you!

Can you explain the meaning of the writer in this paragraph? i'm joining a forum for men. My task is to help adult men have a better relationship with women (sorry if this topic can offend someone). Now i was given to translate a book. But i have a confusing paragraph: "There are no rules you need to follow or actions you need to take prior to the sex to somehow steer toward a particular type of relationship. Many people believe you need to date longer to get to know each other deeply first if you want what they call a “more serious” relationship for instance, but that is simply not the case. If you want a long-term relationship, you can and should decide it after having had sex, without rushing into it. There is nothing wrong with wanting a long-term relationship with one woman, but a real man would not commit to one woman quickly [...] This approach is also a lot easier than changing your manners all the time, and it assures that you will not end up with a female who is no fun in bed " Why does the write say "This approach... all the time"?