I’m not nervous, at least, no more than any other shuttle flight.
If anything, this flight will be safer than most of the others because of all the extra preparation they’ve done for this mission. They’ve had the last two and a half years to analyze every detail of shuttle operation to see if they can do it better. As with the aftermath of most disasters, they’ll be more aware than usual of anything that could possibly go wrong and thinking about how they can avoid it.
The Russians have lost cosmonauts on two missions, Soyuz 1 in 1967 and Soyuz 11 in 1971. They didn’t hide either incident, although they didn’t always go into tons of info on what caused the spacecraft failure.
For Soyuz 11 especially, they would have had a hard time hiding the loss. The cosmonauts were coming back from spending three weeks on board the worlds first space station, Salyut 1. Russian television ran broadcasts of them showing off in zero gravity. All of Russia was well aware they were up there and would certainly notice if after the flight the cosmonauts were never spoken of.
The three were given a large state funeral. US astronaut Tom Stafford was even one of the pallbearers.