12th house Mars in Aries square Capricun't Saturn and Cancer Jupiter with a not-so-nice trine to Moon.
Assertiveness is interesting. Growing up, I had to be careful where and when I used that tactless moron of a mouth of mine, least it land me in deep trouble. Then there was that terrible temper....
Lets see, assertiveness is more than just shouting ones opinion at any given moment (that's actually obnoxious), it's about being able to stand up for yourself when life throws unpleasantness your way. This includes, yes, standing up for yourself with words or actions. Sometimes, that assertiveness also means making hard choices for the sake of your inner peace - like walking away from those that do not benefit you.
So, yes, I am very assertive, but tactfully so now that age has toned down that temper.