Believe it or not,
consciously or unconsciously - we calculate and factor in certain
attributes or qualities of our potential partner to deem if he/she
is suitable for a relationship. Love and Relationship is strongly
co-related, however, they are still separate entities (meaning you
can love someone, but you choose to opt out in a relationship
structure). You must understand that you had an immerse crush on
her, but it is not the same way round. She treated you like a good
friend, with improving impression, but do you consider it anywhere
near the border of love? Not entirely.
Because you do not belong to the category of guys whom she will
have hasty infatuation for - you have tap on honest, dependable
characteristic to sell yourself. This is a good thing and
do
not be discourage with whatever you are
doing.
And because she doesn't fell hard enough, technically, she has her
own rights to choose the kind of partners she seek. Reality is
pretty cruel: do not presume that just because you treated a girl
well and shower all your love and affection onto, something gonna
happen. Something is amiss here; regardless of the goodwill and
stuff you always did, she just doesn't fall hard enough... for a
relationship to begin on proper basis.
Therefore she has chosen an alternative: attempting to shape her
given variables to convince her heart to accept you into a
relationship. Her psyche would probably react like this:
'Ok fine, I think he's a good
guy. I don't know if I love him anot (or even so,
not till that extend), but I don't mind giving him
a chance. But I must have that reason for myself to
give him that chance.
Advice? 
There's no such thing as zero risk in relationship: there's no
relationship without tears as well - it's all about decisions and
the path we opt for. If you have come so far, just to give it up,
you got to tell yourself that you won't ever look back and
regret.
You could also TRY to fill-in-the-blank with what's missing
currently and create a relationship with her. It could be difficult
to define each other's love definition, individual expectation, etc
- however, we will learn two very important skills: compromising
and evolving. It will be difficult though, but at the very least,
you won't regret having to give up when you had the advantage to do
something about it. 
Cheers
