The worst thing you can do is over-egg the pudding. Gushing, affected sentiment is inappropriate and cringe-making. On a pedantic grammatical level, it’s ‘condolence’, not ‘condolences’. But that aside, the bereaved person, at a funeral for example, has likely been offered sympathy all day long and is probably sick of the exhausting attention when they’re just trying to get through the day as quickly and quietly as possible. A gentle handshake, and “I’m sorry for your loss, please accept my condolence,” will suffice.