When correcting or clarifying:
In fact
In reality
In truth
As a matter of fact
When adding emphasis:
Truly
Indeed
Genuinely
For a direct replacement: 
Really
Precisely
Absolutely
Read full article
                        
                    English Hindi Dictionary | अंग्रेज़ी हिन्दी शब्दकोश
When correcting or clarifying:
In fact
In reality
In truth
As a matter of fact
When adding emphasis:
Truly
Indeed
Genuinely
For a direct replacement: 
Really
Precisely
Absolutely