Similar word to simplehearted:

artless, being oneself, candid, childlike, credulous, direct, easy, folksy, forthright, frank, genuine, homey, ignorant, impulsive, inartificial, ingenuous, innocent, instinctive, laid-back, naive, plain, primitive, provincial, real, rustic, simple, simplehearted, sincere, spontaneous, straightforward, trusting, unassumed, uncontrived, undesigning, unembarrassed, unfeigned, unforced, unlabored, unpolished, unpretentious, unschooled, unsophisticated, unstudied, unworldly, up-front