A few things worry me about this.
Principally, she's been single for 2 years and you haven't asked her out yet!!
You are either
a. Shy
b. Have a fear of rejection
c. Fearful of another bad relationship
d. Gay
She probably thinks
a. you're not interested
b. you are 'damaged' beyong repair
c. Gay
Why has you're Mum not done something?
Is it because
a. She thinks you're not interested
b. She thinks the woman isn't interested
c. She actually doesn't like her, or more probably she's not good enough for you (no-one ever is)
d. She thinks you are gay
For gods sake, it's been 2 years, do something asap and put yourself out of yours and her misery