Is it permissible for me to travel to another country to visit a righteous sister whom I love for the sake of Allah, despite the presence of unveiled women in that country?

It is not permissible for a young man to establish a personal relationship with any girl under any name or description, such as "love for the sake of Allah" or "friendship," for these paths are ruinous pitfalls. One must beware of the beginnings of forbidden love by refraining from repeated glances and thoughts, because if it takes hold, it becomes difficult to repel. If the young man desires a lawful way out, he must marry this girl, by visiting her guardian to marry her, so that his contact with her becomes lawful. If he does not intend to do so, then he must distract himself from thinking about her.