It was narrated that Ma’qil ibn Yasaar said: A man came to the Messenger of Allaah (peace and blessings of Allaah be upon him) and said: “O Messenger of Allaah, I have found a woman who is from a good family and is beautiful, but she does not bear children; should I marry her?” He told him not to. Then he came to him a second time and said something similar and he told him not to marry her. Then he came to him a third time and said something similar and he (peace and blessings of Allaah be upon him) said: “Marry the one who is loving and fertile, for I will be proud of your great numbers.”
Narrated by Abu Dawood, 2050; al-Nasaa’i, 3227; classed as saheeh by Shaykh al-Albaani (may Allaah have mercy on him) in Adaab al-Zafaaf, p. 132.
There are two ways of knowing whether a woman will be fertile:
1. By looking at her other family members i.e. her mother and sister.
2. If she was previously married then that will be known from that fact as well.
Marrying the one who is loving means the one who loves her husband and the fertile means that one who will bear lots of children.
If a woman is fertile but not loving then it is not recommended to marry her. If a woman is loving but not fertile then the purpose of marriage which is to bear children and increase the number of the ummah will not be achieved. These two qualities may be known in the case of virgins from their relatives, because relatives are usually similar, physically and in attitude, to one another.
And Allaah knows best.