I think for most men it's never a matter of having a "marriage mindset". There is never any urgency for a man to get married.
Men generally don't approach dating with the idea, "She could be my future wife".Not many are likely to decide they are "looking for a wife".
I myself believed I would never get married....
And then one day you meet someone that opens your heart in a way no one ever has before and before you know it you're making plans for the future.
Note: I told her I didn't see myself getting married!
For a lot of men they "discover overtime" that one by their side after a few years is the one.
Honestly there is no way for you to avoid men who want to stay single. Some men will say whatever they think you want to hear in order to have sex with you. Therefore you can't go by their words alone. Love & Romance requires a calculated amount of risk taking. The more experience we have the better instincts we develop.
It doesn't hurt to ask men if they see themselves gettting married, having children and so on. However anything they say can't be seen as YOU are the one they see themself marrying.
This is especially true we've only begun dating each other.
The problem with asking these kinds of questions early on implies the asker is just about ready to say YES to anyone who pops the question. Talking about marriage before you have even gotten to know someone is leading with you heart and not your mind.
A man want to get married but YOU may not think he's marriage material.He may be asking himself, "How can I avoid the women who want to stay single?"