How do I stop coworker simping for me?

I have a coworker at my current job who keeps simping for me from time to time (unsolicited favors). And while she is attractive, I'm not interested in dating right now, especially somebody from my work. So, previously I just kept ignoring those favors hoping she will understand that I'm not interested and will leave me alone. But now it gets to a point when it's uncomfortable to not reciprocate. And I'm sure that as soon as I start reciprocating those favors it will move into more favors from here which most likely eventually will softly force me into some sort of relationship. So how can I reciprocate, but at the same time make it clear that I'm not interested in any relationship without telling it directly to her?