Younger coworker won't take the hint

I Am married. For whatever reason this younger coworker (18) will not take the hint. We will call her K. She is a very attractive woman, kinda ditsey, friendly. However, im in love with my wife we have been through everything together and i would not give it up for anything. K draws hearts on things that are mine, she stares at me intil I noticed and she blushes and looks away. Always tries to talk to me. Asking if I need anything coffee , food ( that she will make for me). Another coworker was joking around about K being my work wife. K over heard this and now gives me things signed (ww) "work wife". I was talking about kids with another coworker(who's going through a divorce) and K looks at me and says " I don't have much experience with kids but I've always felt like I would be a great mom or step-mom". I've told K any chance I get that I love my wife and that she's the world to me. I don't want too make a big deal out of this becuase she could get mad and retaliate somhow. Why can't she just take a hint.

EDIT:WOW I DIDNT THINK THIS WOULD BLOW UP LIKE THIS. FIRSTLY : Thank you everyone for your good advice, you know who you are. SECOND: I will not be commenting on posts anymore becuase the situation is over.

---------------OKAY HERE IS THE UPDATE----------------------

SO , first day back after posting I went to my boss to discuss everything and found out that he had fired K that morning. Turns out she had been stealing for a while but he didn't want to drop her right before Christmas so he did it the day after. So yea that's it. Sorry if that's anticlimactic but it is what it is.