Michonne didn't think you actually liked her. She didn't think anyone was capable of liking her in that way.

So when you confessed, she didn't believe you.

A few days pass, and she comes up to you asking if you really wanted her.

You nod, "I want it all, won't leave a breadcrumb." You grin.

"What? I thought Rick said some." She paused.

Then you realize, the reason she didn't believe you was because Rick said you wouldn't love all of her.