Translating mic sensitivity dBV to dBSPL
94dB-SPL is a sound pressure level of 1 Pascal. This is the standard sound level used to characterize microphone 'sensitivity'.

A sensitivity of -46dBV means that when a 1kHz tone with intensity of 94dB-SPL is present at the microphone, it will produce an rms output voltage of 5mV. If you double this signal voltage using an amplifier then the effective sensitivity of the mic+amp is -40dBV, but the sound input for that output is still the same 94dB-SPL.

This figure means very little unless you know what the sound level relates to. A jackhammer at 1m distance produces 100dB-SPL, and hearing damage occurs over 85dB-SPL. So 94dB-SPL is far above the maximum sound level that the microphone will likely be used for. A more reasonable maximum would be 74dB-SPL.   

If your mic+amp produces -40dBV from 94dB-SPL then at 74dB-SPL you get -40-(94-74) = -60dBV. If your 0VU level is -10dBV then you need a further 50dB of amplification to get full volume from a 74dB-SPL sound.

Sound pressure, showing sound-pressure-vs-frequency at different perceived loudness levels.