People always start off a relationship giving the best version of themselves. It's the same as when you go to work you wear work appropriate clothing, you don't go dressed in sandals and pajamas (unless it's pajama day).

It's not "deceit," it's working to actually become a better version of yourself. I wouldn't never insist that a partner accept me for who I am--flaws included. We all have things we have to work on, we all are on a journey to be the best versions of ourselves, and our partner helps us achieve that.