The H3+ is a key ion in the interstellar chemistry. The rate of recombination of H3+ with electrons, α, plays a pivotal role in the level of ionization of interstellar plasmas. Over the past 50 years a number of studies of this recombination have been carried out, yet they did not lead to an unambiguous value of α. We report observation of the rate of de-ionization of H3+ as low as αeff ~ 3×10-9 cm3 s-1 at hydrogen density decreasing down to 5×1010 cm-3. This implies that the dissociative recombination of H3+ under interstellar conditions is very slow with αDR<<10-8 cm3 s-1. This value is in agreement with theoretical predictions and astronomical observations, and provides an explanation of the `enigma of H3+'.