Никита Хворостенко 2

function func(string $strStart, string $strEnd) : bool
{
   $strStartChars  = str_split(trim($strStart));
   $strEndChars    = str_split(trim($strEnd));
   $strStartChars  = array_diff($strStartChars,    [' ']);
   $strEndChars    = array_diff($strEndChars,      [' ']);

   foreach( $strStartChars as $char )
      if( in_array($char, $strEndChars) )
         unset($strEndChars[array_search($char, $strEndChars)]);

   return count($strEndChars) == 0;
}