They can only accept, no one can really understand and I think that's the difference.
It's like a math problem. If you can solve it, you understand it. You're in the class with other people that understand the problem. If you can't solve the problem then you don't understand the problem itself. You can come to accept that the answer is correct, because people who do understand the problem are in that class and tell you that that is the answer. From there you can either accept the answer without really understanding it yourself, or refuse to accept it because you can't personally understand it to back it up with personal knowledge. Without actually being in that class, you're only really at a level of accepting; not understanding.
The terms "understand" is thrown out there in a way that more means accepting in an empathetic manner. Like people saying they understand what someone is going through after losing a love one, but they actually can't because that loss is personal to that person and can't be compared. How they perceive and handle it won't the the same way you might or have done in the past. You can empathise and imagine what they're going through, you can never fully understand.
I dunno, I'm genuinely of the impression that it's not something that should be discussed and more just accepted until much further down the line. If it's a date, I'd like to think on a date it'd be more talking about the people we are and interests and not so focused on one persons problems. That's kinda the worst thing to do in a date. It doesn't seem like a good starting point and more off putting than pro-active. I wouldn't want to be on a date with someone where they start trying to make me understand their problems with anorexia or bulimia (other dysphoria examples). That'd actually put me off the person; it doesn't seem appropriate on a date. And I know I'm not alone. How many have been on dates with people who talk about their ex and get out of there quicktime? I just personally don't think it's something worth going into in detail early on. Even if someone says they want to understand, I still read that more as they want to get to know you better. They want to know who you are for them to get why you identify as a gender contrary to sex, and not so much a lecture, books, graphic discussions. When people get to know you, they grow to "get" why you're trans because they see how you act, interact, dress, portray yourself, etc, etc and they now "understand" you.
I still say that personally, I'd tread softly, and I wouldn't share emotional turmoil with someone until I get to know and trust them and sharing the negative aspects of our lives becomes something we both share and not just that one person, and that takes time. Simple questions, yeah. Explaining dysphoria and gender VS sex and binary and so on, it can be just too much too soon and likely that's how the other would see it. Anyone on a date wants a boyfriend or girlfriend, they're not looking for a problem, they can better deal with emotional problems each other have further down the line when they've secured that boyfriend/grilfriend and they know they're worth the time and patience.
I view this as like anything else. EVERYONE has problems, trans or not. Let those problems be addressed later on down the line. If it's a date, advertise yourself for who you are, not explaining who you are. Put the positive out there before bringing in the negative. And bring in the negative when that starts to become a shared thing rather than throwing everything on the table early.