$requirement=~s/. /.\\n/g;
$requirement=~s/, /,\\n/g;

push(@CHECKLIST,{
    ...
    _4_requirement=>$requirement
});    

##</code><code>##

my $article00_Tk=$L00_Tk->Frame()->pack(-side=>'left',-padx=>1,-pady=>0);
my $article00_L=$article00_Tk->Entry(-relief=>'ridge',-borderwidth=>2,-text=>$CHECKLIST[0]->{_1_article},-font=>'Arial 8',-width=>15,-state=>'disabled')->pack();

my $article00_L_Balloon=$article00_L->Balloon();
$article00_L_Balloon->attach($article00_L,-balloonposition=>'widget',-msg=>$CHECKLIST[0]->{_4_requirement});

my $article00_Tk=$L00_Tk->Frame()->pack(-side=>'left',-padx=>1,-pady=>0);
my $article00_L=$article00_Tk->Entry(-relief=>'ridge',-borderwidth=>2,-text=>$CHECKLIST[0]->{_1_article},-font=>'Arial 8',-width=>15,-state=>'disabled')->pack();

my $article00_L_Balloon=$article00_L->Balloon();

##</code><code>##

a)    $article00_L_Balloon->attach($article00_L,-balloonposition=>'widget',-msg=>" text ....");
b)    $article00_L_Balloon->attach($article00_L,-balloonposition=>'widget',-msg=>$CHECKLIST[0]->{_4_requirement});