I have no recipe for how to combine things. But you must be sincere. And if you are, strangely, it will succeed.
But what is the good of friendship if one cannot say exactly what one means? Anybody can say charming things and try to please and to flatter, but a true friend always says unpleasant things, and does not mind giving pain. Indeed, if he is a really true friend he prefers it, for he knows that then he is doing good.