Colorful text in the same line in TRichEdit

if you are using themes... answer above won't work..
you cannot see any colors... till you remove seFont from styles..

RichEdit1.styleElements:=richedit1.styleElements-[seFont];

eg.

....
amsg:='Hola';

RichEdit1.SelStart := Length(RichEdit1.Lines.Text);
RichEdit1.SelAttributes.Color := acolor;
RichEdit1.Lines.Add(amsg + sLineBreak);
RichEdit1.SelLength := Length(amsg + sLineBreak);

You're on the right track. Just change SelAttributes and use SelText instead of Lines.Add:

procedure TForm4.FormCreate(Sender: TObject);
begin
  RichEdit1.Clear;
  RichEdit1.SelAttributes.Color := clBlue;
  RichEdit1.SelAttributes.Style := [fsBold];
  RichEdit1.SelText := 'This is bold blue text.';
  RichEdit1.SelAttributes.Color := clRed;
  RichEdit1.SelAttributes.Style := [fsItalic];
  RichEdit1.SelText := #32'This is italic red text';
end;

This produces