What is the ruling on a father rejecting a suitor for his daughter without getting to know him, under the pretext of her young age, while the girl desires and agrees to the marriage?

It is not permissible for a woman's guardian to prevent her from marrying someone she agrees to, if he is a suitable match. This is an injustice and an act of 'adhl (unjust prevention) forbidden by Allah. This was a practice of the pre-Islamic era of ignorance (Jahiliyyah), and Allah has commanded the marriage of single women. The father must fear Allah and hasten to marry off his daughter if she finds a suitable match and needs to marry, and not make flimsy excuses, for the Prophet, peace and blessings be upon him, said: "Three things should not be delayed: prayer when its time comes, a funeral when it is ready, and a single woman when a suitable match is found for her."