Mourinho is now working under Abramovich for the second time and believes the past decade has shown the Russian's passion for Chelsea and football.
"I remember when Roman bought Chelsea, there was always the question 'when is he going to sell it?'" said Mourinho. "'Is he in love with the club? Is he in love with football? Is he doing this for the right reasons?'
"Now, he's proved it and the value of Chelsea in this market is huge. I'm 100 per cent sure that even with a big offer, Roman doesn't sell. He's proving year after year the objective.
"Some other clubs and some other owners, I'm not sure. I don't know them, their feelings, where they want to go, when they want to stop. Maybe why they are interested is my question mark.
"Roman made life easy for the new owners. Because he did it in the right way, he's giving space for the new people to be seen as a good thing.
"When somebody comes and buys a club and they start investing, some are not doing it the right way. But Roman gave them, by being one of the pioneers, space to make mistakes. He gave them space to be well received and start work.
"In our first time it was hard because Roman was the man on the spot. After that my profile added to it. We were not loved and people were not giving us the credit we deserved at the time. We deserved completely that credit."