The following story is related on the blog momof14:
Rav Kanievsky told him "The next time you meet a girl, talk to her about your scar on the date and tell her the story about what caused you to have this scar". He didn't understand what difference it would make by him telling his story since he knew that if the girl does not like his scar then it doesn't matter what caused it.
A 25 year old yeshiva bachur was still not married. Usually, yeshiva bachurim get married at ages 22, 23, not older than that. So a 25 year old boy is considered old if he is not married by then. This boy went out with girls and after the first date, none of the girls wanted to continue going out with him. He had a scar on his cheek that looked like a cut which didn't look so good to the eye. He was an amazing boy, good middos, Yiras Shamayim, he was a really great boy. But every girl would go out with him on a date, she would see his scar, and there would be no second date after that. Therefore, he got to the age of 25 and he was still not married. So he went to HaRav Chaim Kanievsky shlit"a and he tells him "Kvod HaRav I don't know what to do. I want to get married. My friends are all married and I am still in yeshiva." And he told him that he thinks that it's because of his scar.
One or two months passed by and a girl was suggested to him. He looked into her, and he hears that she is a very special girl with Yiras Shamayim, and exceptional middos. He asks what she looks like and he is told that she looks good. This made him feel worried because he prefers that she is not going to be so good-looking because he knew that if she was really beautiful then she definitely won't be interested in him. So he thought to himself "Maybe she doesn't look as good as people say; nobody ever says about another person that she doesn't look good even if she is not so attractive." So he decided to go out with her.
On the way to the date he was very nervous. He was hoping that she wasn't so good-looking. He was hoping that maybe something would come out of it. When he got there, he saw that not only did she look good, she looked stunning. She was gorgeous! He was very disappointed because he knew that a girl that looks like this would never want him. He went over to her and they started talking. He noticed her looking at his scar. As they were getting into a deeper conversation he saw how everything that he heard about her was really true. She had good middos, Yiras Shamayim, she was truly a special girl. As hard as it was for him, he decided that since Rav Kanievsky told him that he should tell his story about his scar then he is going to do it. So he told her "I am sure you realized the scar that I have on my cheek. Rav Kanievsky told me to tell my story about this scar on the first date so I am going to tell it to you."
He told her that 5 years ago, when he was 20 years old, he came back from Yeshiva in Jerusalem. He was learning in Mir Yeshiva and when he left it was late at night and it was very dark and deserted. All of a sudden, he heard a young Jewish lady screaming. He saw an Arab man running after her and trying to catch her.