Hi,
your apps and softwares are in :
/Applications, or :
/Applications/Utilities, or :
in the users' Applications folder (~/Applications)
I guess what is in your Trash is the files (.dmg, .pkg...) you downloaded and used to install your apps.
These files can be deleted (they are no longer used).
However, they are now useless if and only if you actually installed your apps in their dedicated folders as explained above.
Could you give some example of the files you don't dare to delete (name and extension) ?