Hi I have added some garlic paste in tomato sauce now it tastes somehow a little strange how to get rid of that?
If "strange" means like the garlic paste is rancid (or otherwise spoiled), then throw it away and start over. If "strange" means too garlicky, then your best bet is to add more tomatoes to dilute the recipe, then adjust as needed with other ingredients. You may want to take half the sauce and freeze it for another use then add another can or two of diced tomatoes.
If the garlic paste wasn't rancid, then what it actually might be is simply… raw.
You should have sautéed it in with your onions etc before adding your liquids. that would have softened the 'bite' of raw garlic.
The longer you simmer it, the further back that harsh, sharp, acidic essence will get.
I would give even a simple tomato sauce - olive oil, onion, garlic, canned tomatoes, herbs - an hour at very low before considering it ready to serve.
The initial smell will linger in the kitchen long after the sauce itself has softened, but your diners may actually like the smell. Many people do, they feel it adds 'authenticity'.
Additionally - garlic paste is never going to be a direct replacement for fresh or even frozen garlic, so the base it's in - oil/vinegar/water + preservatives & salt - is going to affect the flavour.
Diluting with more tomato sauce is the standard recourse.
This is why when you prepare food stuff based on garlic -which is a strong ingredient in taste and odour- it is nearly always optimal to plan for both a "light" and a "strong" variation of whatever you cook: tzatziki or skordalia anyone? make sure you give your guests a choice! mix and match, at will!