Don't know how to love?

My sister accused me of not knowing how to love. That was a very hurtful accusation that got me thinking about my personality. After taking one personality test after another, it turns out that I am a very feeling introverted person. I am choleric-phlegmatic. I may feel something intensely but not be able to come out and express it. The other thing that stood out was that I am a thinker. I make decisions logically and not based on feelings. She on the other hand, is greatly moved by emotions. When I fail to react as she would have me to, her conclusion becomes that I am emotionless or unable to love. False, false accusation.

Unfortunately, when people are going through difficult times, I tend to focus more on the solution to the problem. I do not come across as sympathetic even though I may think about how difficult the situation must be for that person. I skip the whole, 'how sad' phase and move right into 'so what do we do now?' She says that the reason I am not married, or seeing anyone is because I haven't a clue how to love. I wonder if she is right. I know sometimes I seem distant, in fact I have been told severally that I tend to come across as unapproachable, but how do I fix it? I can't just walk around like a grinning idiot in a bid to be more approachable. I just think men should stop being cowardly and step up to me, if they are so inclined.

I know I need to work on showing more emotion, being more sympathetic, judging less harshly and many other faults that I am learning are personality weaknesses. But I would appreciate some slack. You know what I'm saying?