well sentences dont have to start with verbs, i know that for sure, it depends on what is the important part of the sentence, but here is why i think the first is more accurate,
يصيب الØب من يؤمن به
means love comes to those who believe "in" it, but the source is clear, its "believe it" not "believe in it" so i think its more like, ur tall if u believe it, or it was a horrible accident if you believe it... so its more like:
بتصدّق؟
i cant put it any nicer way, but i included the second because i know it could work just fine in this context