This newsletter is for those who firmly believe that grammatical analysis — the classical study method — is the true path, unswayed by the sweet talk of today's language industry.
メルマガ is clipped from メールマガジン 'email magazine/newsletter.' 甘言に躍らされる 'to be swayed by sweet talk' uses the passive of 躍らす 'to make dance.' 王道 'royal road, true path' — the orthodox approach. 信じて疑わない 'believes without doubting' is emphatic. こそ marks 文法解釈 as the exclusive focus of emphasis.