Will there be any problems regarding Unmarried Couples stay in hotels in Bangalore?

No there will not be any problem but you make sure you are adult and for best hotel go to Google hotel finder

as long as you're adults, no law can stop you.

No decent hotel in India will give you room if you declare that you are NOT husband and wife. Either you will have to write in the Hotel Register as 'Mr. & Mrs.' or you will have to book adjacent rooms and spend the time together in one room. There are, however, numerous shady hotels which allot rooms on hourly and daily basis. The management close their eyes for a price. They don't care whether the girl accompanying you is your girl friend, sister or mother! Indian sage: Have you ever heard of police raids on hotels? Raids are conducted to detect prostitution which is a crime in India. In the eyes of the police, everybody is a criminal! If you are caught with your girlfriend in a hotel room, the onus of proving that the girl is your wife and not a prostitute is on you.