cautious; careful; solemnly; sincerely (formal)

rigorous; strict; careful; (of writing) well organized; meticulous

cautious and timid (idiom); prudent; careful

reserved; overcautious

to remember with reverence; to bear in mind; to keep in mind

diligent and painstaking

(literary) respectful; deferential

respectfully yours (in closing a letter)

meticulous; rigorous

to respectfully inform (used at the beginning or end of letters)

to adhere strictly (to the rules)

would like to invite (epistolary style)

to guard against; to beware of