1 We must stress that these payment terms are very important to us.
2 Please be aware that this is a crucial issue to us.
3 I don't know whether you realize it, but this condition is essential to us.
4 Our policy is not to grant exclusivity.
5 There should always be exceptions to the rule.
6 I would not waste my time pursuing that.
7 Would you care to answer my question on the warranty?
8 I don't know whether you care to answer right away.
9 I have to raise some issues which may be embarrassing.
10 Sorry, but could you kindly repeat what you just said?