Along with many other people on this forum, I'm not an English teacher or a native speaker, and I don't live in a place where English is the main language. I'm going to share some information I learned by accident from books and websites.
I'm glad if any of this information helps someone.

   1. Every day or Everyday?

       Both are different!

       I don’t want you to come here everyday. [Incorrect]
       I see him everyday. [Incorrect]

       Every day- Means, each day.

                           E.g., I visit myEC every day.
                                   Do you chat with her every day?

        Everyday - It’s an adjective, comes before a noun.
                           Meaning- ordinary, typical, or usual.

                           E.g., Plates and dishes for everyday use.
                                   Street-fights are an everyday occurrence in this area of the city.

                           Everyday life, everyday use, everyday dress, everyday experience etc.

  2. Can not or Cannot?

      Is not, was not, do not, will not, could not etc. are all correct.
      But, 'cannot' is a one word.

      Other examples:
      Goodbye, Schoolteacher, housewife, homework, housework, newspaper.

  3. Maybe or may be?

      ‘May be’ is a verb phrase like ‘can be’, ‘could be’, ‘must be’, ‘will be’ etc.

                          E.g., There may be a strike this week.
                                   The manager may be unhappy with his performance.

      ‘Maybe’ is an adverb. Maybe = Perhaps.

                          E.g.,  Maybe you are right. [ Perhaps you are right]
                                   Maybe she will come with you.
                                  ‘Are you going to sell your house?’ ‘Maybe.’

  4. My dearest husband/wife!

       Beware if your spouse address you like this! :)
       No grammatical errors. But, see the logic.

                          Sunny is a clever student.                                           [ Positive Degree- clever- one boy]
                          Sunny is cleverer than Ren.                                           [ Comparative Degree- cleverer- comparing two]
                          Sunny is the cleverest student in the class.                [ Superlative Degree- cleverest- comparing three or more]

       So, dear wife       [only one is there].
              Dearer wife   [Two are there].
              Dearest wife [Three or more are there]. 

       Means, the spouse can use the word 'dearest' only if they have three (or more) wives/husbands. You are the dearest among all their wives/husbands!

       See you….. :)