Most Helpful Girl
Why not? If she likes you and you like her and she's also interested in men I don't see the problem. In fact, she might be even more trustworthy than most people since she's able to be friends with both men and women and is more attracted to personality than their gender. It isn't like bisexual people are attracted to everyone - they even might have a gender that they hold a preference over.
So yes, it is possible to seriously date somebody bisexual.
Most Helpful Guy
The hell is wrong with some people? What does being bisexual have anything to do with the person them self? I can't stand narrow minded people.