A clear-headed statesman should and would not regret because they make the decision after considering all pros and cons even if the result may pan out differently which is part of the consideration. Most importantly they make decision based on faith, value, right and wrong, not on a short term opportunity. If things go south they should and would bite the bullet than regret.@KYli India may regret their decision for not standing up for Iran and follow the US instruction of not buying its oil....LOL. Iran had offer China a friendly low price for its effort, now let see what India will do.
However from my observation, Modi and the whole Indian leadership abandoned Iran when Trump threatened, they picked China at the border when Trump send USN to SCS, they stopped the border confrontation right after Trump left the office.
So yes, I think Modi will regret because he and his colleagues are opportunists. For that it is easy to predict what they will do, do what they are good at doing "taking opportunities whatever is possible". In doing so, they are always being the one chasing others not leading others.