Why are my search results not showing when I input any body text? Why my search result not showing when I input any body text ?

Are search results based on node title only?

I am creating a multilingual site with French and English languages.

Users should be able to search results by entering any text of a node whether its body text, taxonomy, subtitle and so on.
Core search indexes titles and body content but in order to actually be able to search the nodes have to be indexed.

Search indexes nodes on batches and each batch starts on a cron run.  You can run cron manually by going to your /admin/reports/status but ideally you want to setup a cronjob to do this for you automatically.

Search admin page (admin/config/search/pages) reports on what percentage of the nodes have been indexed.  

Only after the search admin page says you have 100% of the nodes indexed you can be sure that what you search can be found.