What should a young man do whose sexual desire has exceeded his capacity, who does not trust any girl, has not received a clear answer from Istikhara, and wants to get married?

You must marry to protect yourself from what Allah has forbidden, as the Prophet, peace and blessings be upon him, said: "O young men, whoever among you can afford to marry, let him do so, for it helps him lower his gaze and guard his chastity. And whoever cannot afford to do so, let him fast, for it will be a shield for him." Seek Allah's guidance (istikharah) and consult those you trust to guide you to a woman of faith and good character, as the Prophet, peace and blessings be upon him, said: "Succeed with the religious woman, may your hands be dusted with earth (an expression of encouragement)." Have a good opinion of Muslim women, as Allah, the Almighty, said: "O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin." And do not think ill of a woman until her misdeed becomes clear to you, for the default state of people is soundness.