Facts showing the existence of any state of mind, such as intention, knowledge, good faith, negligence, rashness, ill will or good will towards any particular person, or showing the existence of any state of body or bodily feeling, are relevant, when the existence of any such state of mind or body or bodily feeling is in issue or relevant.

Explanation 1."A fact relevant as showing the existence of a relevant state of mind must show that the state of mind exists, not generally, but in reference to the particular matter in question.

Explanation 2."But where, upon the trial of a person accused of an offence, the previous commission by the accused of an offence is relevant within the meaning of this section, the previous conviction of that person shall also be a relevant fact.