What would be a good approach to make sure my advisor goes through all the report?

I would strongly recommend against putting a "trick" sentence into a report, because it looks immature and unprofessional. Remember that your advisor is someone who may be writing recommendation letters for you in the future, or helping you find a job. You want to leave a positive impression on him, and you do not want to appear ungrateful for the time and energy he has invested in you so far (even if you wish he would invest more). That can only backfire on you.

You wrote in a comment that your major concern is,

his all focus is on writing and he never gives me feedback on the main content, which is the primary thing to validate

As a general rule, a good way to get more useful feedback from someone who is very busy is to focus their attention on the specific points you are uncertain about.

For example, when giving your advisor something to read, you can ask him specifically:

• I'm not sure about the way I motivated the problem. Can you suggest any changes to that section?
• Do you think the assumptions I make at the beginning of Section II are reasonable? Did I do a good job of justifying them?
• I'm not completely sure if the results strictly support what I wrote in last paragraph of the Discussion section, what do you think?

By directing your advisor towards your specific questions, you are likely to get much better feedback. (Almost certainly much better than you would get with a passive aggressive approach like putting "trick" sentences into your draft.)

This approach also means that you are taking responsibility for identifying and trying to correct your own weaknesses, which is a very good quality in a student.

Also: if he suggests corrections to the writing of the paper, fix the writing of the paper. Then come back and ask him to read it again, and offer feedback on the contents. Sometimes when the quality of writing in a paper is poor, it becomes very difficult to extract the technical content. It's reasonable for an advisor to ask a student to make a paper readable (by fixing writing issues) before the advisor reads it more thoroughly.

I don't really like to say this, but the first step may well be for you to fix the minor things. If your report is written like your post here, it will take the supervisor some work to follow your argument. I'm not saying it's completely incoherent, but that it could be quite a bit clearer. This places you at the mercy of your supervisor. If you come up against someone who's a stickler for grammar and punctuation, they may be unable to see the wood for the trees, which is to say that they will be unable to follow the thread of your report because they'll be distracted by the "minor things".

Arguabvly this is a failing on the part of the supervisor, but if so it's a minor one. More importantly its an issue that you can address, in a way which helps you in the future. You can assume that if you want to submit journal papers in the future, you'll come up against reviewers who are like your supervisor if not more so. Fixing the small things and (perhaps) improving the clarity of your discussion in advance of that will do you a world of good.

I'm a fan of peer proof-reading when it's appropriate (i.e. when your peers are writing reports at the same level on related but different subjects). It's sometimes forbidden even then so do check local rules, and be sure that your peers don't end up writing bits of the report. Also, be sure to reciprocate. For grammar/punctuation you don't need an expert in your subject. Again, check the rules, but if you're really worried (and especially when you start thinking about publication) there are professional proof-reading services.

I am guessing that your first language is not English and I am assuming that your paper is in English. I also see in your question and comments that you are probably not a native English speaker. Some of your grammar is misused, your sentences are bobbled - words used in the wrong order, and other minor readability issues.

Just throwing that out there because you are writing a question asking why someone wouldn't read your paper and I found your short question hard to read. Now if I had to write a research paper in French - which is my second language - my paper would probably not make sense in certain areas and others look like it was spit out of a translation service.

So before you do any tricky things to the professor I would try to find someone that has very good English skills and have them help you rewrite your paper so that the lead-ins to what you call the "main content" are easy to read and make sense. Your attitude about only the "main content" matters is like a web developer that builds a fast website that does a lot of stuff wondering why no one visits it when it looks poor. The "other content" matters.