The form بِعْتُ can coincide across parts of the active/passive paradigm of بَاعَ. Surface resemblance does not by itself settle interpretation.
IssueWeak methodBetter method
PersonCount lettersIdentify attached pronoun
VoiceAssume one readingUse clause and context
RootTreat alif as radicalCross-check يَبِيعُ
When the supplied phrase genuinely allows more than one analysis, acknowledge the ambiguity rather than fabricating context.