I am just not understanding why you feel that choosing the right
saddle for her is YOUR responsibility? And she hasn't even ridden the
bike yet? Aren't you putting the cart a little in front of the
horse? Let her choose HER OWN saddle. Otherwise she will never
assume ownership of the decision. And you think that helping a woman
with her bike is going to allow you to "hang out [together] more
often"? Nope, sorry, it doesn't work that way! And you're NOT going
to have any fun riding with this woman because she's completely out of
shape. You will get bored as hell riding slowly enough to stay with
her, and she will get angry and resentful because you are faster than
she is. If you want to be honest about it, basing your relationship
on cycling is more likely to cause disagreements between you than it
is to improve your friendship. Let's face it, chances are that she
will stop riding completely when she finds out how out of shape she
is, and how hard it is going to be to get in shape. Most people are
afraid of "hurting" while they get in shape, and I'll bet she is one
of those. Find another woman with whom you have more in common, and
not necessarily cycling, because women are notorious for changing
their interests weekly! She'll be interested in mountain biking this
week, and something entirely different next week. Don't be afraid to
remain single; don't be so "needy" for a relationship; and let the
women seek YOU out if they are interested in you. The only kind of
woman you're going to please with your present attitude is the kind
who wants to make you do everything for her, but since women like that
will never admit their own helplessness, they will never show you any
appreciation for what you do. You don't want that.

Been there, done that, and didn't even get a tee shirt. Listen to the
voice of experience.