I wonder if a sin that is repeated after one made tawbah (repentance) will the first sin be forgiven or will the tawbah not count since I read one of the conditions of tawbah is sincerely not to commit the sin i.e. you have fought hard the temptation of not committing the sin instead of easily doing it and hoping for a forgiveness.
Dislaimer: I am not a muslim.
A saying is often falsely attributed to Rumi that even if you broke a vow ten thousand times, do not let it keep you from repenting again and again. While Rumi may not be considered authoritative by all - obviously sufis are not particularly likeable in the minds of some modern minds - the sentiment goes back to accepted hadiths, as one stated in the linked site that roughly says that repentance is possible until death.
That being said, Sassir's comment points to the cause of your doubt; resolving not to commit again whatever you repented for, later commiting the act again does not negate your resolution at the moment of repentance being genuine. To be frank though, this seems a bit legalistic and neglecting the heart of the matter: Islam teaches you to strive for what it considers goodness sincerely, and this should be your only concern if you want to follow Islam. This kind of accounting will only make you bury your head in details and neglect the overall picture. In religious terms, Islam exhorts you to strive to please god sincerely while relying on (without trying to exploit) and taking solace in mercy.
@Sassir comment on question: "I think you misunderstood the correct formulation is stop doing this sin ("immediately") and intent not to commit it again (intent here needs to be understood in Arabic as 'azm عزم, which is more likely to be equal to intent, as it means one "decides" not to do it in future, while intent in the meaning of niyyah نية is starting immediately and should hold for the duration of an act of worship etc.), but who knows the circumstances that may come in future. Of course it isn't a good sign for the thawba being "accepted", but redoing thawba and istighfar is never a bad thing"