subjunctive with conditional
Hi, I have a question about the subjunctive with conditional. In the sentence "estoy seguro que vendría" this is just a simple present with conditional. But if you use "no estoy seguro que..." this means the subjuntive right? How would this sentence end? Thanks.
2 Answers
Yes you're right, verbs of doubt and negation require the subjunctive in subordinate clauses:
No estoy segura de que venga. I'm not sure she's coming.
on the other hand, expressions of certainty or belief such as estoy segura de que .... take the indicative
eg. Estoy segura de que viene. I'm sure she's coming.
An example of the subjunctive with the conditional would be:
Si yo fuera rico compraría un ferrari.
The reason you can use the subjunctive here is that your being rich is seen as hypothetical and unreal at best, unlikely at worst 
But when you are talking about something that is seen as real or likely you just use the indicative.
Si llueve mañana, no iré.
PS Just watch with using 'seguro que' as if often should be 'seguro 'de' que' - the trick is that if you can replace the 'que' with the pronoun 'eso' you will need to use the 'de' before the 'que'.
Eg. No estoy segura de que venga. I'm not sure she's coming.
= I'm not sure 'of' that
(I'm not sure that. - doesn't make sense, so you need the 'de')
In addition to Kiwi's excellent answer, I think one thing that confuses English speakers in things like this is that there is no "conditional subjunctive". Because of this, there is no direct literal way to say "I am not sure she would come". You can say "I am not sure she is coming",as in Katy's answer, or you could say "I am not sure she will come" using the future subjuctive, but this is very rare and not in general use.
Just one of those differences in the languages!
