Y'all are tripping. There isnt any yaoi, it's not even insinuated. Sure, they're a cross dresser but theres nothing romantic between them. Dont let those commenters scare you off.
This is an entertaining manga about a high-class assassin who is utterly awkward around woman. He saves a crossdressing marriage con-artist to get their help in finding a girl to fall in love with. If anything's, this may end up being a Harem than BL.