Readings & Meanings:
I checked my compatibility with him in the blood-type-horoscope.
The mysterious liquid emitted a very nice smell.
The police investigator found the perpetrator's bodily fluids* on the victim's body.
San-zui (the three-droplet form of 水) on the left.
The phonetic on the right (液) gives a sense of "pile up."
If you collect enough drops, they will pool into a liquid.
Bonus: Blood-Type Horoscope
Do you know your blood type? If you're an American, you probably don't, or it's not in recent memory. But if you're Japanese, you definitely now your blood type, and you know what it means.
In Japan, the blood type is regarded as more important to personality than the stars under which you were born. Western-style horoscopes, like Pisces, Sagittarius, etc., are not as popular as blood-type horoscopes. Especially for your compatibility tests.
The girl in the example sentence is typical of this mentality. If she's an A-type, she probably wants another A type. Although when I was in Japan, I think O-type was made very popular because of an O-type character in a popular ドラマ. See below for a short chart of types, taken from Wikipedia.
Best Traits: Earnest, creative, sensible, calm.
Worst Traits: Fastidious, overearnest.
Best Traits: Wild, a doer, cheerful.
Worst Traits: Selfish, irresponsible, arrogant.
Best Traits: Cool, controlled, rational.
Worst Traits: Critical, indecisive, unforgiving.
Best Traits: Agreeable, sociable, an optimist.
Worst Traits: Vain, careless, ruthless, cruel.