that I think about it
Je pense qu'il faut que j'y réfléchisse.
I think I need to think about it.
Il va falloir que j'y réfléchisse.
I’ll have to think about it.
I have to think about it.
Il faudra que j'y réfléchisse.
I'll have to think about it.
Il faut vraiment que j'y réfléchisse un peu plus.
I really need to think about it a bit more.
Il vaut mieux que j'y réfléchisse aussi.
I'd better think about that too.