If a cis person meets a trans person and the trans person introduces themselves with a name that doesn’t match what appears to be their gender and they are working (meaning possibly their employer requires them to use birth name or something) what should that cis person do?
If they are doing so because of a shitty employer, drawing attention to their real or perceived gender nonconformity could make things worse for them. You could also just be wrong and actually looking at a man that seems feminine to you; it’s very common for trans men to be assumed to be trans women if we’re not passing as men.
I recognize this is absolutely coming from a place of compassion and empathy, but the best thing to do with a stranger is take them at their word and be courteous. There are a ton of things that could be going on when someone introduces themself with a name that seems to contradict their gender presentation, and trans woman forced into it is only one of many possibilities.
To generalize: in general, defer to the person’s judgement. If they’re giving their real name or their dead name or whatever, assume they did their own tradeoff calculations using more info than you have access to and just go with it, but also be willing to change if they decide to change their decision.