My (38F) friend said she will ruin a friendship if I (39M) don't date her

I'm a widower with a 12 year old daughter. My wife died 6 years ago and it was super hard on both me and my daughter.
I've been focused on being the best parent and I can be and with support from family plus therapy for us both, we're managing okay. I do know how hard it was for my daughter to make friends for a while after that.
For the past 2 years she's had this really good friend. They are pretty much inseparable. I've seen the difference this friend has made to my daughter's life and it's been amazing.
The friend has a mother who is also a single parent. We started interacting more a year ago when our daughters got closer and I thought we were pretty good friends. A few weeks ago she said she had feelings for me. I do not feel the same way unfortunately. She's a great person but I just don't feel that way about her and I was honest about it.
She didn't take it well, and I empathize, I think we've all been there. But in the past 2 weeks, she asked me again. She's said things like she wants me to give it a chance, she feels we'd be great together and "it's good for the kids". 2 days ago, she said she might have to restrict her daughter from being friend with mine because it's a 'painful reminder' to her about me.
I really really don't know what to do. Her friend cutting off contact will set my daughter back and really mess with her. And I will feel 100% responsible for that. But on the other hand, being forced into a relationship feels so wrong and weird. It's not fair to anyone.
Any ideas at all? I have no idea how to proceed
TL;DR: Daughters friends mother said she wants me to date her. I don't feel the same way. She's threatening to ruin our daughters friendship as a result.


Source.