I always read the profile.How else am I supposed to know if we have anything in common, or if I am interested in her?

Ok let’s start with an on line scenario:

We both signed up in the same dating app. You checked out my profile then I checked out your account too we post in the forums and at a distance we observe how each other is by the way we express our thoughts and by the way we communicate with others. We got more interested and one of us sends that first message which later turned out to be the start of so many more. Days go by we like each other even more we start to feel that elusive connection we both yearn for. Then suddenly messaging wasn’t enough we wanted to see each other and video was the next step. Gosh we liked each other even more . What we saw just made the attraction even better. We admit to each other that we like each other more. Then video chat would later on not suffice anymore. We want the real thing , yearn for the real thing.

So my question goes:
Dear mingle men.....when and how do you know that what you feel is the real thing already when you haven’t even met the girl personally? Is there a time frame that makes you realise yes she is the one? When do you realise it’s more than infatuation? Do you sort of do a test to know your true feelings and hers too? Is there a certain level of love that you feel that makes you want to be serious with a girl and would want to spend happily ever after? Basically these questions are about the on line stuff which I know is quite different from the real world. I would appreciate your opinions and personal experiences without any judgements.

Thank you all in advance