Hi Mascara. I'm a Cancer with Cap Rising/Moon. I think I understand both signs fairly well.
Your first post is very telling in that you mention you are trying to regain her trust. So, you did something that fubared the relationship. One thing that is very important to Cancers is honesty and trust. It really depends on what you did as to whether you will be able to regain her trust. If there was the slightest hint that you were interested in another women or just lied to her, that is a huge blow to a Cancer. The fact that you immediately assume she must be interested in someone else is also a tell of a guilty conscious since we immediately blame others for our own transgressions. Cancers, like Capricorns, usually keep their deep emotions buried. Unlike Caps, we have shells and will retreat inside and it is VERY hard to coax us back out. And if we feel someone has broken our trust it is very difficult to win it back. If this is the case give her space. Sending her romantic texts is slapping her in the face. Cancers are VERY romantic and dreamy about love. When we perceive a hurt it cuts us to the core.
Now, if you didn't do anything wrong, forgive me for implying you did. Cancers do jump to conclusions. You need to take a good look at the relationship and what is in it for you. If you need someone calling you everyday and constantly texting and she's not going to do it, move on...she isn't the woman for you. You didn't mention if this was a long distance relationship or if you are in the same town. You didn't mention dating or how serious this relationship is. Or, if in her mind you are just friends. Cancers take their friendships very seriously, but yes, we do need lots of alone time. We don't like crowds or feeling crowded. If you can't deal with that, then she isn't the woman for you.
Have the two of you ever had a discussion regarding the type of relationship you want to have and what your expectations would be of it and each other? It may be too late to do so in this case, but it is very important to have that discussion in future relationships instead of trying to figure out what is going on because you aren't talking with each other. Communication is key as is honesty. Cancers don't like to share their feelings and neither do Caps but if you want to have a relationship you need to.
Evaluate what each of you bring to the relationship and what you are getting from it. It needs to balance out for both of you. If you are the one doing all the compromising and chasing and you are tired of it, then stop doing it. If she isn't meeting you half way now, she never will.
If you still want her in your life and you both had agreed you were friends then go slow and just be friends. Cancers love having friends. That is the way to prove to her that maybe she misinterpreted your actions or whatever caused her to mistrust you. Cancers pay attention to actions and not words. If you say you love her, show her by being loyal to her, not by chatting up other women in front of her....or whatever it was. Sorry falls deaf on Cancers' ears...especially for repeated behaviors. Sorry means you will never do it again not sorry you caught me this time and I will continue to do it more subtly next time. Cancer can forgive if you never do it again.