In my experience, and experience of other males friends, the females indirectly hint at these subjects. Like talking about how friends of hers are getting married, and how happy the couple are together.
or, talk about some friend of hers who is having a baby, and how nice that is. And how her friend is lucky to have a wonderful man, but that her friend is not as lucky as she herself is to have YOU.
The females dance around these subjects if they are interested in marriage, and then you are supposed to pick up on it and take things from there. They just don’t want to do the asking themselves.
Sometimes it's a little more direct. I know somebody who has made no secret about having NO interest in getting married ever. His girlfriend, who has always said she is fine with that, emailed him a photo of an engagement ring. Guess she's not as fine with the arrangement as she's been saying... In my opinion, not a smart move on her part.