【Notwithstanding】 , 【in spite of】 , 【despite】 are often interchangeable prepositions.
【Notwithstanding】 , the least emphatic, merely implies the presence of an obstacle; 【in spite of】 , the most emphatic, suggests active opposition or strongly adverse considerations to be encountered; 【despite】 is somewhat lighter in its emphasis than 【in spite of】 and otherwise is closer to 【notwithstanding】 than to 【in spite of】 < 【notwithstanding】 the rain, I shall go> <I shall go 【in spite of】 all your efforts to prevent me> < 【despite】 his assurances, I doubted him>