You can use an adverb such as actually or a phrase such as in (actual) fact to emphasize that something is really true, or really happened, or is surprising:
It looks as if Tony is actually doing some work.
There’s a big difference between saying you’ll do something and actually doing it.
In actual fact, she was quite right.
Other adverbs such as absolutely, acutely, positively, totally and utterly add a stronger emphasis:
The food was absolutely fantastic.
His voice changed and became positively angry.
You’re being utterly unreasonable.
Another way to add emphasis is to use one of a wide range of adjectives such as blatant, breathtaking, complete, gross, unadulterated and utter:
That is a gross distortion of the truth.
What a load of unadulterated nonsense!
She’s the complete opposite to me.
It was a complete and utter waste.
Other adverbs such as moreover, basically and furthermore also add emphasis to the point you are making:
More and more people are opposed to the idea of increasing university fees. Moreover, there is now evidence that it discourages many students from coming to the UK.
Basically, you should have asked me first.
There are very many phrases that can be used to add emphasis. Here are a few of them:
All this is going to cause a lot of trouble, believe you me.
Everyone talks about sexual equality, but the fact remains that women are paid less than men.
I can’t even begin to imagine what it’s like for him, bringing up three kids on his own.
I would like to point out that the 50,000 or so home educated children in Britain are the lucky ones.
I can assure you that it is most certainly NOT okay to ask someone if their child has a disorder.
Muffins and pastries are usually very high in sugar and saturated fat, and quite possibly packed with hydrogenated veg oils into the bargain.