Venus-Pluto conjunction: Can anyone tell me which is stronger ?

Pluto is the stronger of the two. pluto is in the sign it rules which increases it's strength in the chart. venus is in it's detriment in scorpio, which makes it more difficult to express this energy, thus weakening it. further, when an outer planet makes an aspect to a personal planet, it is always the personal planet that needs to conform, not the other way around. fortunately for you it's a fairly loose conj, making the influence weaker than it could be.