Halachah: We rely on this nowadays, in that we do make use of women.

Translation: This (Sofrim) means 'Talmidim'.

Translation (cont.): And 'Ravak' is a bachelor - who has never been married ...

Source: The Targum of the Pasuk in Yeshayah (40) "u'Bachurim Kashol Yikashelu" is 'u'Revakei'.

Reason: Because his lust is stronger than that of a married man.

Explanation #1: Rashi explains - even with many women,...

Explanation #1 (cont.): ... and specifically a peddler, but anybody else is permitted.

Question: The Ram queries this however, from the Gemara above (on Daf 81a) 'If the men are inside and the women outside, we are concerned about Yichud' - implying that it is unanimously prohibited for any man from secluding himeself even with many women?

Explanation #2: Therefore Tosfos explains 'Lo Yisyached im ha'Nashim' - even if one is together with one's wife, which the Gemara permitted earlier (on Daf 80b) ...

Reason: ... because since he is a peddler, there is more reason to suspect him.

Clarification: According to his Mazel (See Tosfos Yom-Tov) ...

Source: Because 'Life, Parnasah and children do not depend on one's merit, but on one's (predestined) Mazel (Mo'ed Katan 28a).