Congruence officially is when the lines of a triangle are the same as one another (or some shit like this I don't take math). But in seduction, it means having your frame being in tune with her feelings.

A frame is what unites multiple threads of conversation from one minute to the next. It is your personality within the conversation. And while what your frame is commonly like does make up your personality, one can have many different frames for different moods and different situations. Obviously your demeanor in court is different than your demeanor at the bar. Even if you get asked the same thing in each of those situations, your frame determines how you respond.

It is important to keep your frame when talking to people. That is what shit test are doing, they are trying to see if you will break frame and take on a temporary disappointed frame, or shocked frame, or whatever. If you look for the frame in people, it will be quite clear to see when they are changing frames.

Now it is true that you shouldn't change your frame to be congruent with the mood of every new individual you talk to, that would make you have a weak frame that is liable to change more easily. But that doesn't mean you can't adjust your tone within your frame to become congruent with a girl. It isn't breaking frame to briefly empathize with a girl having a rough day. You gotta read the girl, and present your frame in the most accessible way possible.

For instance today I was in a dance class that a club was offering at my Uni. Every five minutes or so we were paired up with a new random girl to dance with. Some of the girls I could tell were happy to be dancing with me, others not so much. To the smiling girls I smiled back and gave an enthusiastic hello. But to the less happy girls, I waited. I was lower energy but still had my confident frame, I especially was concerned with intense eye contact. And the fact that I had matched their level of excitement meant that I was on the same page as them, and it was the first thing I had in common with them. And it became easier to get them to crack a smile and start to like me. I didn't get any numbers this time because it was the first lesson, I hadn't the time to make strong connections, and a public rejection would be really bad social proof. But the grounding is there.

Be congruent but stay in frame.