I spot Chinese philosophy, so here's some info: 庄周/庄子 (Zhuang'Zi) once said “且君子之交淡若水,小人之交甘若醴;君子淡以亲,小人甘以绝。”
Focusing on the first sentence, and the main origin of the concept, 君子淡交 (jun'zi'dan'jiao) literally means gentlemen (should) have "light" relationships. The kanji are not conflicting because in this case the "light" does not mean "not close", it means that the relationship is elegant, simple and direct. ZhuangZi believed that true gentlemen's relationships are built on free, open relationships without the need to be wary, always overtly humble as in oriental culture, or put up polite farces. If one faced trouble, there is no need for long pleas and thorough rationalizations, all that is required is a short notice, and help would be given with trust.
Keep in mind that in the past, meeting or contacting one another is not a simple task, especially for travelling learned scholars. Therefore, the emphasis that all noble friendship requires is trust and faith makes a lot of sense.
edit: I forgot to mention that in the context of the original quote, being gentlemen is a prerequisite to having a relationship as "light" and clear as pure water, since gentlemen are broad-minded, open and don't really care about worldly desires like fame, power, wealth (hence they won't scheme or try to deceive others)