Alonso wasn't afraid to voice his opinions after several incidents with McLaren in 2015
Renault say they discussed Fernando Alonso's reputation for outspokenness with him before signing the two-time champion to return to F1 in 2021.
Team boss Cyril Abiteboul said a break from the "toxic" F1 environment had been "important" for the Spaniard.
Abiteboul said Renault had focused on "making sure we don't let him down by over-promising and under-delivering".
"We've taken the time to be clear ... about where we stand today and where we will stand in 2021 and 2022," he said.
Two-time world champion Alonso's willingness to speak his mind about the position of his current team has caused tension at times in his career.
Among several incidents, he famously called McLaren's Honda engine a "GP2 engine" and said it was "embarrassing" over the radio at the Japanese company's home race in 2015.
And when he was with Ferrari in 2013, he provoked a public rebuke from chairman Luca Di Montezemolo when he told a TV interview who asked what he wanted for his birthday: "Someone else's car."
Frenchman Abiteboul said in an exclusive interview with BBC Sport: "We discussed that. It is also one of the reasons why it was important for him to take a year off, to walk away from the sport.
"You know, let's not underestimate how ruthless, how toxic F1 can be.
"No matter how hard you work, how hard you try, how good you think you are, sometimes it is just not possible.
"And I think that is what at some point burns out every one of us except maybe Toto (Wolff) and Mercedes and Lewis (Hamilton). And doing this sort of break is the best guarantee that these things will not happen again."
Alonso will turn 40 mid-way through the 2021 season, a similar age to Michael Schumacher when he made an unsuccessful comeback in 2010-12.
But Abiteboul said he had no doubts Alonso could perform at the highest level in 2021.
"It is not a worry," Abiteboul said. "It is something we take on board. We have taken the time to discuss (it).
"What matters most is not the physical status or situation, it is more the motivation. I guess that one thing that is impacting your level of performance at a certain age is your level of motivation.
"His motivation is strong, and therefore in my opinion, age is not a factor for the duration of our contract."
Renault signed Alonso following a pre-season driver swap for 2021 in which Ferrari decided to replace Sebastian Vettel with Carlos Sainz and Daniel Ricciardo decided to leave Renault and sign for McLaren.
But Abiteboul said Renault's discussions with Alonso dated back four years to 2016.
"Discussion started way before Daniel's decision to leave for McLaren," he said. "I don't know where things would have got us if Daniel had made a different decision but clearly, let's be honest, the timing of Daniel's decision was not helpful - we were focused on other aspects.
"But that being behind (us), today I am very comfortable with this decision."
-- Courtesy of BBC Sport