~~incontestably, inexpressibly incomparable.
Intractably inscrutable.
Indiscreetly in on each others' intimate secrets.
Intrepid, independent, individual.
Infinitely ingenious interior designers.
Indisputably, inexhaustibly, indecisively infuriating.
Insanely indulgent, incorrigibly inquisitive.
Incalculably inconsistent, inalterably intransigent.
Infernally incommunicative, indubitably incomprehensible.
Ineluctably, ineffably intriguing.
Indescribably, infectiously incandescent.
Infallibly inexplicable, invaluably intuitive.
Intrinsically instinctive, intelligent, insusceptible.
Infuriatingly innocent, intensely, intoxicatingly interesting.
Inescapably inestimable, incontrovertibly indispensable.
Incredible.