What that might look like is a person who professes deep interest and desire for you, then as you move forward, just suddenly breaks it off and says, "I hope you understand but I have to move on." It can leave you quite confused and with that feeling as if someone has just pulled the rug out from under your feet. Usually when people genuinely lose interest and no longer feel that a relationship is a good fit, there is discussion about what they perceive is not working well, rather than a vague expresrsion of, "I just have to move on."
3. He gives inconsistent explanations or avoidance. Almost all of us have had the experiences of dating a person who is inconsistent with explanations. For example, you might make plans to get together and find that the person cancels at the last minute or just doesn't show up. Later the date may explain, "I'm so sorry but I had to drive my cousin to another city so was a bit out of pocket."
This sounds reasonable enough until the person lets slip, "Yeah, it was a long four hours trip driving my daughter to college." Whoops! Was it a cousin or daugher that got driven to another city?
When you say, "Oh I thought it was your cousin," then the story changes to, “Well actually it was a family trip because my ex went along since we both wanted to support our daughter. I didn't want to call or text you because our energy together is so negative since we still don't get along. I really didn't want to expose you to that.”
How considerate of the date ... not! The real story is that the person is probably still hooking up with the ex but did not want the ex to know that he or she is actively pursuing another relationship with you.
Similarly if you are dating someone that travels a lot and you ask, "Oh when you travel to New York, do you stay with friends, family or grab a hotel or an Airbnb lodging?" and the answer is silence or a change of subject, that is not a good sign. People, who travel frequently and do not have other relationships in other cities, have no difficulty saying, "I grab a room or rent a condo, or stay with friends." They will also stay in touch with you while they are away.
Online dating can be a wonderful adventure but keep the above signs in mind to help you sort through the wonderfully abundant princes and princesses who do exist, and the frogs who may be people in attached realtionships masquerading as being single.