How do you know if a woman is really interested in a man she's with? Can you tell from the outside?
Some women are truly skilled manipulators who can create a completely genuine narrative,, but they can do that even when their faking it.
Also, from my findings and experience, once a women do kids with a man, they'll do anything in their power in order to keep him..
There are usually obvious signs, mostly with body languag, eg she's quiet and respectful with that sort of giddy, free spirited sort of feminine energy around her guy, and where the guy i is not walking on egg shells or subdued in any way but has the calm and masculine presence to him. Another obvious tell is the kind of chemistry they have and to what extent they engage in any sort of PDA, however minor it might be - if she's holding his arm for instance that's a pretty clear indicator.
I will say though, it's not always so obvious. That's why I think it's a mistake for us to judge relationships we see in the wild, because you never really know what is going on behind closed doors. In other words, if it appears kind of normal/neutral, it's ambiguous to know how she really feels about him, you have to kind of observe them for a long time or in an intimate setting to get an idea.
If you're asking this question for determining how
you can determine how interested she is, this is a lot easier. The old adage is if you have to ask, the question is probably no. So if she consistently gives you mixed signals or is disrespectful, that means she's probably not really attracted to you and may already be looking to get out. However women will stay with a man even if she doesn't respect him, because they like having the power and control in a relationship.