Am I sinful if I donate clothes that might be worn outside the home, even though they are unsuitable for going out, which could lead to their use in disobedience to Allah? And should I donate them to a charity? And will I receive the reward if they do not reach the deserving?

If you predominantly believe that the clothes you intend to donate will be worn by the recipient in front of non-mahram men, then do not donate them, based on the Almighty’s saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." However, there is no harm in giving them to a trustworthy charity organization. You can hope to receive reward for it even if the clothes do not reach the deserving individuals, as Al-Bukhari titled a chapter, "Chapter: If one gives charity to a rich person while unaware." This is supported by the hadith of Abu Hurairah concerning the man who gave charity to a thief, a prostitute, and a rich person, and his charity was accepted due to his good intention.