regard vs pertain

regard is a noun but pertain is not a noun.

Word	Noun	Adjective	Verb	Adverb
regard	Yes	No	Yes	No
pertain	No	No	Yes	No

As verbs, pertain is a hypernym of regard; that is, pertain is a word with a broader meaning than regard:

Other hypernyms of regard include bear on, come to, concern, have to do with, refer, relate, touch, touch on.

regard (noun)	pertain (noun)
a long fixed look
(usually preceded by `in') a detail or point
paying particular notice (as to children or helpless people)
an attitude of admiration or esteem
(usually plural) a polite expression of desire for someone's welfare
a feeling of friendship and esteem
the condition of being honored (esteemed or respected or well regarded)

regard (verb)	pertain (verb)
deem to be	be a part or attribute of
look at attentively	be relevant to
connect closely and often incriminatingly