Honestly. As a friend or coworker, I would have zero problem. To date, no. I have zero interest in dating anyone with a vagina or even who used to have one. I thought the whole gay liberation movement was, why can’t we love whom we want??? We don’t pressure gays to date the opposite sex. Don’t pressure people to date trans people either, please.
That would be my first inclination, but to be true to conservatism/reality, don't think it would be possible long-term. To be friends you'd have to play along with the fantasy that that he is a "she". That would be impossible for me.