Like someone who just got out from a relationship? Don’t rush things. He/she maybe in the hurting stage. What you can do is at least just be there for him/her.
Now, If he/she is entertaining you, again.. DON’T RUSH THINGS. Chances are he/she is still inlove with the person who broke her heart. But you can help him/her heal. Forget. Always make him/her happy. Let them know you’re always here for them. Now when you see clearly that they moved on, time for you to move in! :-)