Putting it all together, the user is likely saying "Madhuri Dixit's buttocks are my best" or "Madhuri Dixit's ass is the best". However, this is a very informal and potentially offensive phrase, especially since it uses a vulgar term in a language to refer to a celebrity.
First, the phrase seems to be in Hindi/Urdu mixed with English. "Madhuri Dixit" is a famous Indian actress, so that part is clear. "Ki" is a possessive particle meaning "of" or "belonging to". "Gand" in Hindi/Urdu means "anus" or "buttocks". Then "mari best" is in English, meaning "my best". madhuri dixit ki gand mari best
The user might be trying to create a meme or a joke, but it's important to note that using such language, even in jest, can be inappropriate. Also, using a celebrity's name in this context without proper context could be seen as disrespectful. Putting it all together, the user is likely