Dinner and a play are the classic ingredients of a night out, and the speaker begins by treating them like a bill to settle: "I owe her dinner and a play." It sounds almost like an apology, as if the evening is something he has been putting off. The tone is light and a little teasing, but there is real affection under it.
The poem then turns in an odd, playful direction. The "many little witty expressions" seem to be the speaker's own clever remarks, and they "call to her." The strange image of a bear arriving "with a dish of myself" suggests he is offering up his own personality as part of the meal. Judging by the wording, the speaker may be a bit clumsy or shy, a big, awkward creature trying to be charming. The mood is warm, humorous, and slightly self-mocking. The short lines and missing punctuation make it feel like a quick, half-spoken thought rather than a polished speech.