Authors:

If a guy truly likes you, but for personal reasons he needs to take things slow, he will let you know that immediately. He won’t keep you guessing, because he’ll want to make sure you don’t get frustrated and go away.

Greg Behrendt, Liz Tuccillo (2009). “He's Just Not That Into You: The No-Excuses Truth to Understanding Guys”, p.13, Simon and Schuster
If a guy truly likes you, but for personal reasons he needs to take things slow, he will let you know that immediately. He won’t keep you guessing, because he’ll want to make sure you don’t get frustrated and go away.