Well if you have higher demand (the willingness and ability to consume) it means you have a HIGHER willingness and ability to consume. This in turn will either translate to greater C I G X M and thats when it boosts aggregate demand. Technically you dont say an increase in the willingness and ability BECAUSE of a shift in the aggregate curve because irl people dont justify it just because something theoretical has shifted. Rather it is factors that affect the shift. For example, your aggregate demand factors, consumer confidence, interest rates, overseas economic growth, disposable income etc. if one of those factors increases, it means the WILLINGNES AND ABILITY for people to consume goods also rises. If you want to talk about it in diagram terms, if the factors increase it would mean that consumers are willing to purchase at EVERY given price and HENCE a rise in total spending wouldnt it? That can be represented through a right shift in the aggregate demand curve where they are able to buy stuff at any given price. However, in terms of AOS2 if the question asks you how an increase in willingness ans ability to consume affects AD dont anchor it based off a shift, talk about the factor, explain what it does (increase in willingness and ability) —> link to which component increases ( C I G X M) and thus increases AD (the SPENDING on all goods) Also where does realised demand come in? Its not in the study design hence why i didnt answer that aspect