Only God can truly know what is in someone’s heart (1 Samuel 16:7), but throughout life God will often reveal the hidden things to us through a variety of practical means (Daniel 2:22).
When I use the phrase “keep the door open,” I’m referring to you leaving your options open with someone rather than intentionally closing those options or proactively making a definite move to date this person.
We should never blame Satan for our sins. Even when we are tempted, the Bible states that we alone are responsible for our own choices (James 1:14-15).