Instead, be honest with him. And if you truly think there's a possibility that you'll fall in love as you get to know him more, let him know about it (without making any promises). Be sure to use the word "I," so he knows it's all about you and that he didn't do anything wrong.
For example: "I really like you, and I love the time we've spent together. But I'm not ready to say those words yet. And I don't want to say them until I'm totally, 100% sure I mean it."
When (and if) you're finally ready to say it, you'll be glad you waited.