To the men help a sis out !

I don’t have brothers or male friends, so I’m seeking advice for future reference. How can a woman truly tell if a man has good intentions and is serious about marriage from the start? Please don’t mention the obvious, like “asking for your father’s number,” because SOME men use that as a bluff to appear serious knowing some girls may be like “ oh it’s too soon let’s wait a little bit”. so what are the real signs that show a man is serious about marriage, or the subtle signs that we as women may miss that indicate he isn’t? Words can be misleading, and it’s hard to rely on them alone. I feel like men know men better than anyone else would so I’d like to hear your thoughts!